Here's the thing...let's say the citizens lynch incorrectly on night one, and score gets to 8 citizens vs. 10 rebels. Is there anything in the rules to prevent the rebels from identifying themselves to each other in the thread? Assuming that they do that (while they have a numbers advantage), they can then just run the table on the citizens.
I didn't post a rule because I figured it would be a common courtesy thing and they wouldn't do it. That and they wouldn't want to give away their roles. There is still a Hit out there and a possible botched hit, not to mention the bodyguard protection. So IMO it wouldn't be smart till it got closer to the end of the game.
But to ease minds
Rebel factions may not tell other rebels factions that they are rebels,either by PM or on the thread.