Yes, but I hope they don't. The law may be the law, and Mt Gox can improve, but he doesn't deserve to be arrested for this.
Definitely not. Something like this should never lead to jail time. They are registered for their main business so it's obviously just an oversight. I bet a hefty fine is all that will be levied.
I do remember the heavy handed way the Feds dealt with the online poker companies though. Hopefully this isn't that kind of ridiculous overreaction.
No one will go to jail. Big banks get caught laundering money for drug cartels and just get a fine. BOA gets caught screwing people out of their homes, they get a fine. The US Govt much prefers money then a trial.