Actually, I'm not sure that that's functional yet.
To my knowledge, the only limitations we can put on accounts is very much an "on or off" thing. They can either log in or they can't.
When I'm able to (and can get to it), I will change the way that works. I will implement timed suspensions (like SI has), and terminations/suspensions for individual aspects, including public posts, chairman functions, thread creation, and PMs. In most cases, if someone is suspended, I still want them to be able to access PMs. And the jail board.
Bob