What’s the risk of sending to known invalids under CAN-SPAM?

CAN-SPAM doesn't technically forbid sending to invalid addresses. But that's a trap. The real risk is operational and reputational, not legal.

Here's what actually happens. When you send to addresses that don't exist or have been inactive for years, mailbox providers flag you as a low-quality sender. They track how many of your messages bounce and how often subscribers report spam. High bounce rates signal poor list maintenance. ISPs don't trust senders who don't clean their lists. They'll throttle your mail, delay delivery, or send you to spam folders. Most ESP terms of service also explicitly forbid repeated sends to bounced addresses. Violate that and you'll lose your account or get flagged for suspicious activity.

The second angle is your sender reputation. Hard bounces hurt faster than you'd think. Even a 5% hard bounce rate looks like negligent list hygiene to ISPs. You're signaling that you don't validate addresses before sending or you're not removing dead email addresses from your list.

The fix is straightforward. Clean your list regularly (at least quarterly for most senders). Remove hard bounces immediately after they occur. Use an email validation tool on your list before major campaigns. It takes a few hours and saves you months of reputation damage.