I also tried with both the composite cables and an RF cable, and they were both giving this problem - though if it was a problem with the TV "liking" the NES, that would make sense, wouldn't it?
As for more games using more pins than others (like the other guy was saying), the game I tried it with in the store didn't have pins all along the bottom of the cart (DK classics) and both of mine that I tried (SMB and Elevator Action) did, so that also makes sense...