If your members posts are indexed by search engines and they have profanities then those will show up in the results. Are only guest posts available to search engines?
You could have a plugin that uses regex to check the content and xxx out any that are in a list (or replace them for a daft word of your own).
--------------- Added [DATE]1373579416[/DATE] at [TIME]1373579416[/TIME] ---------------
You can try this, create a plugin using hook "newpost_process" and enter the following
PHP Code:
if (!is_member_of($vbulletin->userinfo, 1, 2, 3)){
$badwords = array("monday", "tuesday", "wednesday", "thursday", "friday");
$post['message'] = str_replace($badwords, "flowers", $post['message']);
}
replace and add to the bad words list, the usergroup staement says if the user is NOT in usergroup 1,2 or 3 then perform the replacement.
Change the usergroups and give it a go in a test environment as i haven't tested it