You're right, in that the customer would pay the tax. But also its not like they could be charging an extra 20% and be getting more money. They will have put significant effort and research into finding out what the optimal level of pricing is to get the most grift, which means the fall in "sales" from putting things at a higher price would outweigh the increased profit. I'd rather them scam less and let the government get at least a slice of it. Though really, more regulation to stop this kind of exploitation would be better.