I've never dealt out a TPK as GM, but then I don't believe in resurrection either... I can only remember playing in one, and that was a long time ago.
However, I think it's right to say that seeing a DM outrageously dodge killing a PC when they really should die, can be almost as disconcerting as dying when you don't reckon on it. Some years ago (not in D&D), I had a long-lived and well-loved character recklessly (but very typically) enter a blazing building - to try to save some animals - which was about to fall into a very deep hole. When it promptly did so he should have died, but by excessively obvious referee intervention he didn't - and playing him afterwards felt like a bit of a cheat. Individual player kills are a different kettle of fish to TPK - if it happens, it happens.