Being allowed to talk in that channel shouldn't be a reward/privilege, but it sounds like it could be an interesting channel, if it were to have rules of its own (for people who are already banned) that are (generally) tougher to follow than the other channels. And if you make a mistake in that channel, you'd go back to 5 days.
If we're gonna do that, then the question is what kind of rules it should have. I have an idea in mind where each banned user is randomly given a set of 3 (?) existing channels that they have to follow in that channel at once (only combinations which can be unified, of course).