voted: Surprises are okay, but give the setup. Players should know how many mafia/cops/docs etc. there are.
I don't really like to be messed with by the mod. Surprises are okay, like the one in Improbable Role Mafia. I liked the twist that there's a chance that a voter could be killed as well (that didn't turn out too well for me btw). But when you get a role, and the E-mailed description is different from the true role you got, I think it sucks. I've had it more than once.
So, surprises during the game are okay, but don't say anything that turns out to be different (I don't like lies, unless I'm mafia).
This is just my opinion! I think it's up to the mod what to put in his game. After all, it's his/her game.