I'm of the opinion that players should always know all the rules pertaining to their character's abilities - and I mean that sentence both ways, since players who don't know the rules that govern their PC's capabilities frustrate me as a fellow player, much less as a DM.
I think it's absolutely reasonable to insist that players not attempt to persuade the DM with metagame arguments - I've seen people say dumb things like "I'm pretty sure a guardroom full of unsuspecting orcs would be louder than you seem to be assuming, so my character should know whether or not this is the guardroom door he's listening at." That kind of statement ignores a whole range of DM knowledge about the situation - whether or not there are multiple rooms with noisy inhabitants which could be mistaken for the guardroom, whether or not the guards are rowdy, whether or not the guards are as unaware as the player assumes - and there's no place for it in the game as far as I am concerned.
More realistically, players who demand to know the source of an NPC's ability to survive their PC's assault - "How could he make that save? What level is he? He can't possibly have a modifier big enough!" - are far more common, and perhaps even more irritating. The DM can have secrets, and players should accept it when she does.
To me, though, the idea that the players of a game should be kept ignorant of the rules affecting their PCs' abilities smacks of the worst kind of "GM = God" thinking from the early days of the hobby.