Well, no prob, if he hasn't been rebanned, you can always just put his status as that of a troll. It effectively does the same thing without deleting the profile. They can watch, but never participate.
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)