Ok, so first pass gives me a TERRIBLE idea, that would "get the job done". I'm sure you thought of this and dismissed it: Keep your "overall bounce rate" low,

Ok, so first pass gives me a TERRIBLE idea, that would "get the job done". I'm sure you thought of this and dismissed it: Keep your "overall bounce rate" low, by ALSO sending out extra emails to confirmed email addresses. Like, for every "confirmation" email, also send a "thanks for joining us" email to someone that already confirmed their email.