Although it may be possible to ban people from one forum only, I'm pretty sure the vast majority of bannings are complete - No posting anywhere.
As for the announcement of names, I dunno. If you really wanted to get pushy about it, I could be banned. I was banned under another ID (That I won't reveal), & came back to this one that I'd had longer, but never used. Obviously I learned my lesson, & I now consider myself to be a reasonably upstanding member of this BBS. If the person is coming back & raising hell again, then by all means ban them & expose their real identity. But if they've come in and are re-establishing their reputation... Why bother with them? They aren't causing any harm, & you've accomplished your goal that you originally banned them for - You solved the problem.
Just my $0.02.
Viper GTS