When a creature is invisible but not hidden, one could argue that the players still know it's general location. If a creature becomes invisible and not hidden does it remain on the battle-mat?
Specific example - If a rogue successfully hides from one opponent can he then sneak attack that opponent? Or can the opponents allies use a free action to yell out, "Hey, the annoying guy with the ...
Hiding requires an opposed roll. Can a sleeping character hide at all? If they do so, do they roll Hide when they go to sleep (for hiding their sleeping spot, etc.), or do they make an opposed roll ...