I've done it openly in threads, but only in rare, egregious cases. It's usually done by freepmail. And it's done quite a bit, actually. I've never, however, seen a creationist criticized for posting fraudulent quotes, or other clearly discredited arguments. Some will repetitively post the same material. They even get praise from their fellow creationists for refusing to back down. Nothing even remotely comparable to that happens on the evolution side.
That's good news, then. I, also, have utilized FREEPmail to head off potentially disastrous lines of argumentation. I suppose it goes on wherever you have people who actually care about each other in the group.
Our lack of mutual civility usually results from not being able to see inside the other group, and as a result, we don't offer them the benefit of the doubt.
I have several brothers who are a variety of shades of atheist/agnostic/evolutionary/deists/whatever, but that doesn't affect my love them or my admiration for their achievements in life.
It's a different world on the threads, though. I will stand for my belief in God, and His creation, 'til the day I die, but I find no reason to demonize my opponents (although that doesn't mean I won't take advantage of the opportunity to make them think a little harder about what they say).
If there were some way to create a category called "Reasonable, Non-Inflammatory, Christ-like, Non-condescending, Investigation of Scientific Discoveries, Spiritual Truths, and How They Pertain to the Theology of a Creative God or Not", I'd be a happy camper.
"You bad Creationists give the REST of us a bad name!"
(There: ya happy now; PH?)