The only drawback with my MOD (that I can think of at the moment), is that if you try to ban multiple users, and one of those users is in a group that can't be banned, the error message pops up explaining that. This is less-than-ideal, as I think the best solution would be to ban the users that can be banned, and then present a message saying that such-and-such user couldn't be banned because they are in a group that can't be banned.
The other downside is that this MOD uses the hooks feature to grab each post from viewtopic, analyze whether the user is in a group that can be warned, and then edit the postrow accordingly. One of the developers may want to chime in on this, but I believe this process is slow++. Would adding code to viewtopic.php make it faster?
I'd like to hear thoughts about this for 3.2.x.