I guess that counts? Some of the local burger kings once had an online game they advertised, where you could win free burgers if you are the first on the highscore (the other 2 places got some sort of coupons for cheaper meals), turned out there was a score submit bug you could abuse after finishing a game (me and a colleague noticed, while trying to find some sort of bug), when I reported it they didnt care (didn't get any response, maybe spam filtered?), so I got us some free burgers, scanned in the receipt and send it again, they paniced or just realized you can generate any amount of free burgers for the time of the game being online, took down the game for a day or two, sent me a short email thanking me, thats it.