Force users to update email address

[Ted S]

Why force users with a good email to re-enter it? I'd suggest taking the bad ones and updating their account to remove their emails (you can search by email to find them).

Then with a simple template conditional you can bug them to fix it (or lock down entire pages until they do).

<if condition="!$bbuserinfo['email'] AND !$show['guest']">
Your email address bounced, update it!
</if>

Of course a code edit/plugin would let you completely shut people out if they didn't have a valid email.