Then it's a game of trying to find ways to not pay your affiliates. Do you want to be the retailer than gets known in the affiliate space for trying to find loopholes not to pay what they said they would? People would stop promoting your site. You might as well shut down your affiliate program if you're going to not pay your affiliates sometimes.
It doesn’t look like these guys (or most “affiliates”) are actually promoting the site or driving traffic. They’re just dipping their spoons in the existing money river.