We roll in the open so everybody can see the results, but I never go out of the way to check what everyone rolled - I trust them not to lie (or to get caught by the other players if they do). But like some other posters ahead of me, I do have one player that we all try to watch when she rolls, because she'll occasionally try to make an attack roll with a d12 if we don't catch her.
Johnathan
Johnathan