OlivawR: Valve has an automated refund system for Steam now and it was not abused although people did the same thing as you did and predicted a horror. What makes you think that a system that needs approval from a real human is more abused than an automated system?
Not sure if you can compare those two situations. As far as I know, Valve has very specific requirements for their refund policy. Apparently you can only play a game for a max of two hours, before you lose your rights to a refund. So I guess there's not much to gain by abusing this policy. At best you could use it as a "free" demo period for games, which is actually pretty cool.
Normally you can't abuse GOG's refund policy either, since you only get a refund if you didn't download the game, or if there's severe technical problems with the game. ( And the latter would likely involve much back and forth with GOG's support, before you eventually get your refund. Might as well just pirate the game in first place. )
But in this specific situation ( a user received a game which they have no interest in from a pinata ) I can definitely see how some would take advantage of the refund policy, and perhaps even feel like they "deserve" a refund, despite the fact that GOG never promised customers any specific game. ( Even the listing in the tracker thread isn't official -- they never promised anyone they'd have a chance to receive those specific games. )
At the end of the day, you can bet that
some are taking advantage of this, to increase their chance of scoring an especially valuable game. The only question is, whether or not those are the exception or a significant portion of the pinata sales.