We can't give it an absolutely appropriate answer. Being a huge hater of seventh generation, I like the way of killing developers with this. being a guy who waits for commercial crash of Video Games, if I had access to eBay (witch I never will considering the political collisions) I did it, either selling or buying stock games.
But we should see the other side of it. there's no difference between buying stock games and downloading them via P2P networks or Rapidshare, in the first affair, you directly use your money to be able to play a game witch your money won't benefit the company, in the second one, you use your bandwidth that you paid for, and this won't benefit the developer as well.
So we can wrap it up to this phrase "Convincing". because when you buy a game from eBay, you're convincing yourself that you aren't pirating this game, but you're doing the deed. eventually, we encounter another commercial crash, witch will be good, very good indeed to make developers stop themselves from drowning into losing their mannercrafting by money and interests of rich bitches.