Wow, this is funny. I thought you weren't supposed to tell anyone your role.
I've played this game a bunch, always with kids. I wonder if I'll change my approach? I don't know if the young kids would like the "lying" aspect of pretending to be someone else.
I've always played it that you had to pay close attention to who was doing what. If you're the sheriff, don't shoot someone that wasn't shooting you. Pay attention to who was protecting you, that kind of stuff.
So, it's interesting. One one side, I don't know if the kids (under 10) would appreciate and be able to handle the bluffing aspect. On the other hand, the kids often have a hard time keeping track of "who must be my enemy based on his actions". Perhaps table talk would help with that.
I agree that the only rule is no showing your role untill you are dead. That rule is set in stone. As far as roles I think part of the game is to try to BS your way to the advantage. That said after a few games you learn to never listen to a thing anyone says as they are all deputies as someone stated.
The only voice you can listen to is actions, if you listen with your eyes and see what people do then you can cut threw all the chatter which is part of the fun.
As far as kids go I think they often have a better time bluffing as most adults assume kids can't do it well.