Also, is this the first time bundles are giving away GG keys?
Possibly. I can only surmise that GG was feeling a bit left out with all the publicity Steam and Desura were getting with the Humble Bundles and Indie Royales. There's no other way to explain why GamersGate allowed itself to be associated with such a shitty bundle.
It's not necessarily a cooperation between GG and IndieGala. Developers can ask GamersGate for "Digital Codes" for their games, which can then be redeemed on GamersGate. It's up to the devs (or publishers) what they do with these codes. It's a nifty service actually and I'm surprised that I'm not seeing this more often.
Personally, I bought the bundle. Because 1) I want to support IndieGala for finally releasing a bundle that doesn't require Steam, 2) I'm actually curious whether those simulator games are really as bad as their reputation, I never played one, and 3) It was dirt cheap. :)