I think I agree with the mechanic simply because it balances it out like Jekyl and Ring said. Though I suppose it theoretically could be possible to hide when you're setting a trap. Stealth in itself is really hard to accurately RP I find, as stated by Jekyl. A stealthy character really shouldn't be able to walk accross flat terrain without any cover what so ever. I've actually seen a few servers where Plays can actually get in trouble for stealthing like that, where there is no cover what so ever to at least make it somewhat plausible.