Federal and Local Governments have covered up stuff for the sake of business before. Eric Holder gave HSBC a slap on the wrist for money laundering for Mexican cartels and terrorists in the UK, just because, in his words, if HSBC went down "it would roil markets". You know, laws be damned because markets are more important than jailing criminals and ending their enterprises.
If this was the motive, and I truly think it is the more and more I hear about the guy (and the fact he sounded like a grumpy cunt), there's no way MGM would want that to get out. Or the myriad of casinos in Vegas, for that matter.