[tellyblues]

A contestant touched his ears, when "ear" happened to be the answer to the question. But he and his wife had both already been eliminated, so what reason would he have to cheat?

If an active contestant(s) was involved somehow and him signalling meant he was in for a share of any eventual winnings. Not that this happened of course. Cheating will go unnoticed if a plan is so complex and nobody expects it.