Yeah, but I'd love to see the legal mess untangling that. There would be at least 4 parties to such a lawsuit - Google, their employee, Gigster, and the company who bought the MVP. IANAL, but I believe that such a release absolves Gigster of any legal liability, but wouldn't protect the client from having Google lay an injunction on them for using source code that belongs to Google. If somebody warrants that the goods you are receiving are not stolen and it turns out they're lying, that doesn't prevent you from having to give them back.

The way IP issues usually surface is during diligence for an investment or acquisition, anyway, and most investors won't go anywhere near a company that can't prove they own their IP.