I'm very happy to see that those who got the games were able to keep them. The conspiracy theorist in me thinks that maybe this was a marketing stunt, but Occam's Razor tells me it's just a mistake and they were a good sport about it.
I think it's a bit of both. EA is aggressively trying to lure people over to Origin, they figured, a free game for a survey would be an enticing offer, but after they realized something was wrong they had a choice of letting it slide or cracking down. If they cracked down on the people exploiting the code they would have done the opposite of converting people to Origin. However, now that a bunch of people have multiple games in Origin, they are invested and will likely buy more games in the future.
True [1]. I reckon someone gets fired over this. Exploits never end up good for all.