Ken,
Yes, players must protect their own hands, but tournament poker should also protect all players by assuring the correct player gets the pot. We've discussed this before on numerous threads, turn over all called hands at showdown. We've also debated who should turn over the discarded hand? I believe our rules (TDA) should erase any doubt, as to what the proper procedure should be at showdown.
No player, in for all bets, is allowed to muck their hand without showing.
In the event a player mistakenly mucks, thinking they are in the hand unopposed, they will be instructed to turn over their discarded hand.
It's true, the player without cards should not be awarded the pot. However, in the original question, I would rather confiscate the pot than award it to a player who miscalled his hand, and very probably had the losing hand.
Players must protect their own hand...and the TDA must protect all tournament players.