A frank and open dialogue about hacking

Not sure what you mean by impersonation.
If a person comes on here saying "I am the Dread Hacker Roberts" we will ban him, regardless of whether he truly is said hacker, or even of whether there is such a hacker.
But if someone simply registers by the name Roberts, and says nothing about it, we can't know whether he is the hacker, an impersonator, or just a random person who happens to use the same name.

Let's say there is a guy well known as one of the head hackers through a server, say "AstroDinoMan" just as a made up example. Then someone registers using that as username here and posts as his in-game info that of the well-known hacker. That should be bannable.

We've had it happen before, more often than even I am aware of and I think it's stupid you should wait for them to admit to it even while the rest of the comunity knows its them. Even if that wasn't the true hacker, it takes you knowing who that one is to try pretend to be them and trying to use their fame or w.e.