I'm disappointed by all the folks calling mail fraud a 'loophole'. Mail and wire fraud are the ways people prosecute domestic 419 (Nigerian prince) scams and other confidence games.
This case shouldn't be given a free pass just because the party intended to be deceived is the judicial system rather than the mail recipient.
Fraud terms vary between states, but you're already looking at 10-15 years for commercial fraud before aggravating factors, from what I can tell (I'm not a lawyer).
The idea behind treating mail fraud separately is explicitly that the severity, if not the legality, of fraud should depend on whether or not the mail was involved.
Remember that when mail fraud came into existence as a discrete crime the mail was the primary means of communication for essentially everyone and everything. Tampering with it went beyond deceiving any one person or group of people.
This case shouldn't be given a free pass just because the party intended to be deceived is the judicial system rather than the mail recipient.