I am not an expert on the Federal Acquisition Regulations but I've been involved on the government end of the source selection process before. There are different types of contracts and the source selection process determines how they "weigh" different factors including price. Once the high bidder was selected and the low bidder protested and the government award was upheld. Past performance had something to do with it and also the technical proposal. Nobody went to jail. It's a little different if the bidder has no experience or is determined that they cannot do the job or have little understanding of what is required.

Anyway getting back to Boeing here is a more recent article that explains more.

Air Force Tanker Contract