Non-subscribers receiving marketing emails and submitting unsubscribe requests is a multifaceted issue stemming from various technical, procedural, and user-related factors. These include direct sending, forwarding/wrong lists, DMARC variances among MBPs, data breaches/purchased lists, form stuffing/scraping, typos in signups, poor list hygiene/outdated data, unclear partner signup forms, system misconfigurations, compromised accounts, spam policy violations, incorrect address harvesting, and the absence of confirmation messages. These issues result in emails reaching unintended recipients who then request to be unsubscribed.