The overwhelming consensus from email marketing experts, documentation, and community discussions is that blocking emails solely based on the word "unsubscribe" is a poor strategy. It's unreliable, can block legitimate emails, and interferes with automated processes. Effective spam filtering relies on sender reputation, authentication protocols (SPF, DKIM, DMARC), reducing spam complaints through good email marketing practices, utilizing reputable ESPs, monitoring spam complaint rates, implementing feedback loops, creating safe sender lists, and employing comprehensive IP and domain-based blocklists. Building a quality email list through opt-in methods also significantly reduces the need for aggressive filtering. While blocking might stop some unwanted mail, the risk of false positives and the availability of better alternatives make it an undesirable approach.