Ban addresses for registration ONLY?

[Emor Schnoodgress]

Is there a way to ban an address for registration ONLY...without also banning existing users who have that address?
I see under Configuration/Banning/Disallowed email addresses where it says
"Here you manage a list of email addresses which cannot be registered or used by users." - but I don't want to wipe out all current users of that address!

For example: I'm getting tons of gmail spam. I'm completely willing to tell NEW registrants that they can't use their gmail address to register. But I have quite a few existing gmail users, and I don't want to get 'em angry!

I don't see any such options under "Login and Registration Options"...
Any suggestions?

[StefanT]

There is a setting for this:

Users Keep Email
If a current user has an email already registered in your banned list, should they be allowed to keep it?

[Emor Schnoodgress]

You found it!
I see it!
How did I miss that?
(probably because I skipped over "Users Keep Email", thinking it meant something else)
Very cool,
Thanks thanks thanks...