If you remove a user from all groups (even the "User" group), they shouldn't get errors, they just shouldn't see any forums. When I tested this I could still do searches, see who's online, etc., just no forums. If they log out, they'll still be able to see anything guests can see (obviously). It will prevent them from posting though.
The commands I listed I tried to make compatible to the prior release. If you are running 6.2x, the commands are (just run it through the "SQL Command" feature in the admin panel):
SELECT DISTINCT B_IP
FROM w3t_Posts
WHERE B_PosterID = $User (replace user's user Number)
that gives all the IP's a user has posted under.
SELECT U_RegIP
FROM w3t_Users
WHERE U_Number = $User (replace user's user Number)
that gives you the IP the person registered with.
SELECT B_PosterID
FROM w3t_Posts
WHERE B_IP = 'xxx.xxx.xxx.xxx' (replace IP number here)
that gives you all the people who have posted under a particular IP address. It's usually more helpful if you chop off a couple of the last numbers and use '%' at the end, so it will pull a slightly larger range of IP's.
JustDave has a mod that looks for duplicate users by placing a cookie and notifying the admin if the person logs in under another name. I wrote up a mod that adds the "Show IP" to the admin menu for users, so you can see what IP's the person has posted under.
As for seeing an IP before the person posts, we have the users' (not just anonymous) IP's listed in the who's online for admin and mods to see.
As for the 'you've been banned' language, it's in languages/yourlanguage/generic.php -- $ubbt_lang['YOU_BANNED']. You could easily change the language to say, "We've encountered the following problem:". The language after the colon comes from the "Reason" field when you ban a person. So if you wanted it to say tech. difficulties, you'd just ban them and put "we're experiencing technical difficulties in your area" or whatever. They won't see anything about being banned, they'll just see "We've encountered the following problem: we're experiencing technical difficulties in your are."
