You'd think if they could identify 'suspicious' clicks, they could just ignore them: don't hold the impressions/clicks against the ad-buyer, don't reward the ad

You'd think if they could identify 'suspicious' clicks, they could just ignore them: don't hold the impressions/clicks against the ad-buyer, don't reward the ad-bearing site operator. Problem solved. If it's an honest misunderstanding: no harm done. If it's a money-making scheme: they'll give up and go elsewhere, guaranteed.