IP ban, just for writing?

[Sore Eyes]

Part of our board is open to writing by unregistered users. Because of a silly question mod we have been able to avoid all spam for almost two years now, which is great.

A consequence of this openness is that a ban of a registered user is not effective: he can still write in the 'open' subforums.

Really annoying people DO sometimes get a temporary IP ban, but we dread the fact that the IP ban makes reading of the forum impossible too.

So we're looking for a method to keep some people out of our forum, while they are still able to read it.

Anyone any idea?

Thx a lot