The seller tried to only refund half the purchase amount because I didn't have the original box it was sent in. (I threw the box away before I realized the item was counterfeit.) I had to appeal his partial refund to eBay, who agreed with me that if someone sells you counterfeit crap they have to fully refund you even without the box.

After exchanging several emails with the seller, it was clear that he believed that as long as he gave refunds when people sent everything back to him in mint condition, he had done nothing wrong and did not deserve to have his reputation damaged. The problem with that, obviously, is that he wasted the time of dozens/hundreds of people, and defrauded people who did not notice the item was counterfeit. (People only got refunds if they noticed and requested; they were not automatically told they could get one, as an honest seller would have done.)

Under the current system, sellers face little incentive to make sure they aren't unwittingly acting as a fence for stolen/counterfeit good. Without reputational hits, they only have to reimburse buyers for the purchase price, not for the time wasted, and many/most buyers won't bother to return it anyways.