Are re-engagement email subject lines and practices deceptive and how should you deal with engaging with old leads and unsubscribes?
Matthew Whittaker
Co-founder & CTO, Suped
Published 12 Jul 2025
Updated 16 Aug 2025
8 min read
Re-engagement email campaigns can be a powerful tool for breathing new life into a dormant subscriber list, but they walk a fine line. The goal is to reconnect with subscribers who have lost interest, not to trick them into opening emails or to send unwanted messages. There's a critical difference between a legitimate attempt to rekindle interest and a deceptive tactic that can harm your sender reputation and trust with your audience.
The perception of deception often stems from subject lines and practices that create a false sense of urgency or imply prior interaction where none exists. For instance, using Re: or FW: in a subject line when there's no ongoing conversation can quickly erode trust. This isn't just a minor marketing faux pas, it can lead to higher spam complaints and a damaged standing with inbox providers, ultimately impacting your deliverability.
It is important to remember that engaging with old leads and, especially, unsubscribes requires a very careful and compliant approach. Ignoring opt-out requests or continually sending emails to disengaged contacts can lead to severe consequences, including being placed on a blacklist or facing legal penalties. Responsible re-engagement focuses on providing value and respecting subscriber choices, ensuring a healthy and sustainable email program.
The risks of deceptive practices
One of the most common missteps in re-engagement campaigns involves subject lines that mislead recipients. Using Re: or FW: when there was no prior email thread is a deceptive practice that can backfire. While it might grab attention initially, it immediately breaks trust when the recipient realizes there's no previous correspondence. This can lead to increased spam complaints, which significantly harm your sender reputation.
Beyond subject lines, some deceptive practices include continuously changing sending domains to evade blocklists (or blacklists). This behavior indicates an attempt to bypass legitimate blocks and is a clear red flag to internet service providers (ISPs). Such tactics will ultimately lead to poor deliverability, with emails consistently landing in spam folders or being rejected outright. It also makes it difficult to recover your domain reputation in the long run.
Employing such deceptive email practices is counterproductive. Even if a few emails get through initially, the long-term damage to your email program is substantial. ISPs are constantly evolving their filtering mechanisms to detect and penalize deceptive sending behaviors, making it harder to reach the inbox over time. The negative impact on your sender reputation means a significant portion of your legitimate emails will be filtered, impacting overall campaign effectiveness.
Deceptive subject lines and practices
Using misleading subject lines, like adding Re: to cold outreach, violates trust. Continually changing sending domains to avoid blocklists is also a deceptive signal that mail providers will detect.
The subscriber lifecycle and engagement decay
When someone opts into your email list, there's a natural decay curve in their engagement. This means that over time, unless actively nurtured, a subscriber's interest will naturally wane. There is a golden window for re-engagement, typically within a few months of inactivity. Beyond that, the likelihood of a successful re-engagement diminishes significantly, and the risk of negative impacts like spam complaints rises.
Many marketers and sales professionals find it challenging to let go of old leads, even those who have been inactive for years. This reluctance can stem from the perception that every lead holds perpetual value, or from a desire to maximize every potential opportunity. However, holding onto disengaged contacts, especially those who have not interacted with your emails for extended periods (e.g., six years), can actually hurt your overall email program.
Continuously emailing extremely old or inactive profiles increases the risk of hitting spam traps or generating high complaint rates. These negative signals tell ISPs that your mail is unwanted, which can lead to emails going to spam even for your active subscribers. Prioritizing list hygiene and understanding this decay curve is crucial for maintaining strong deliverability.
Ethical re-engagement strategies
Transparency: Use clear, honest subject lines that accurately reflect the email's content. Avoid deceptive phrases like Re: unless it's a genuine reply.
Value-driven content: Offer clear incentives or exclusive content to encourage re-engagement. Remind subscribers of the benefits they receive.
Permission-based: Only email contacts who have explicitly opted in. For inactive subscribers, offer a clear path to opt-out if they're no longer interested.
Best practices for re-engagement campaigns
Winning back inactive subscribers or old leads requires a strategic and ethical approach. One key best practice is list segmentation. Don't send the same re-engagement campaign to a contact who was active last month and one who hasn't opened an email in two years. Tailor your messages based on the level of inactivity.
Personalization is also crucial. Address recipients by name and, if possible, reference their past interactions or interests. This shows you value them as individuals, rather than just another email address on a list. Craft your re-engagement email subject lines to be clear and compelling, focusing on the value you offer or a simple 'We miss you' message, avoiding any misleading elements. The goal is to reignite interest, not to trick.
Remember, not every inactive subscriber can or should be re-engaged. If multiple attempts fail, it's often best to remove these contacts from your active mailing list. This helps maintain a healthy sender reputation, reduces the risk of hitting spam traps, and ensures your engagement metrics accurately reflect your true audience. Consider a final opt-in confirmation before removal. For more insights on this, you can look at email marketing best practices.
Handling old leads and unsubscribes
Dealing with unsubscribes is straightforward, but it's where some of the most critical compliance issues arise. Once a recipient unsubscribes, you must stop sending them marketing emails immediately. There are very limited circumstances where it's acceptable to email an unsubscribe, primarily for transactional messages directly related to a current purchase or service, not for promotional content. Misclassifying an unsubscribe as a soft bounce is a severe violation of email regulations, such as the CAN-SPAM Act.
Reactivating old unsubscribes is generally not considered best practice and can lead to significant deliverability issues and legal trouble. If you're considering re-engaging old leads, it's crucial to first segment them heavily. Remove any contacts who have explicitly unsubscribed or have shown no engagement for an extremely long period (e.g., several years). It is not common practice to reactivate old unsubscribes.
For very old, unmanaged email lists, a cautious approach is necessary. Instead of a direct re-engagement campaign, consider a strict re-permission campaign where subscribers must explicitly opt-in again. This ensures compliance and cleans your list. Remember that sending to inactive profiles negatively impacts deliverability. Maintaining a clean and engaged list is far more valuable than a large, unresponsive one.
Old leads (inactive subscribers)
Risk: Higher chance of spam complaints and hitting spam traps. Damages sender reputation.
Approach: Segment aggressively. Attempt re-engagement within a reasonable timeframe. Remove unresponsive contacts.
Goal: Identify truly interested subscribers and maintain a healthy list.
Unsubscribes
Risk: Legal penalties (e.g., CAN-SPAM Act), severe damage to reputation, and potential blacklisting.
Approach: Immediately cease all marketing communication. Only send transactional emails if absolutely necessary.
Goal: Ensure compliance and respect subscriber preferences fully.
Ethical email marketing: building trust and deliverability
A responsible and effective email marketing strategy prioritizes building trust and maintaining a healthy sender reputation. This means being transparent in your communications, respecting subscriber choices, and understanding that not every lead can be salvaged. Deceptive practices, while seemingly offering short-term gains, ultimately lead to severe deliverability issues and can damage your brand's credibility. Always focus on providing genuine value.
By adhering to ethical re-engagement strategies and diligent email list hygiene, you ensure your messages reach the inbox of interested recipients, fostering long-term engagement and driving better results. It is far more beneficial to have a smaller, highly engaged list than a massive, unresponsive one riddled with deliverability problems.
Views from the trenches
Best practices
Always segment your re-engagement campaigns based on inactivity levels.
Offer clear value or a strong incentive in your re-engagement emails.
Provide an easy and obvious way for subscribers to opt-out or update preferences.
Common pitfalls
Using deceptive subject lines, like 'Re:' or 'FW:', for cold emails.
Treating unsubscribes as soft bounces, which is a compliance violation.
Mailing contacts who haven't opened an email in several years without re-permission.
Expert tips
There is a natural decay in email engagement from the moment someone opts in.
Marketers should not be afraid to let go of truly inactive leads.
Focus on a golden window for re-engagement, usually within a few months of inactivity.
Marketer view
Marketer from Email Geeks says they frequently block senders who change domains weekly to avoid legitimate blocks.
2021-11-04 - Email Geeks
Marketer view
Marketer from Email Geeks says they recall seeing disclaimers from senders who claim their 'Re:' subject lines are not deceptive, implying recipients simply missed previous emails.
2021-11-04 - Email Geeks
Final thoughts on ethical re-engagement
The key takeaway for re-engagement email subject lines and practices is to prioritize transparency and respect for the subscriber. While re-engagement campaigns can be effective, they should never cross the line into deception. Using misleading subject lines or attempting to bypass legitimate blocks through domain changes will ultimately harm your sender reputation and deliverability.
Engaging with old leads requires careful segmentation and a realistic understanding that not all past contacts will re-engage. Focus your efforts on the segment with the highest potential for reactivation, always providing clear value. As for unsubscribes, the rule is simple: honor their request immediately and completely for marketing communications to ensure legal compliance and maintain trust. A clean, engaged list is always more valuable than a large, disengaged one.
