I actually completely disagree with the idea of letting someone, who signed a contract, cop out at the last second.
Follow orders, do your job, and if you don't want to be deployed badly enough, then do something stupid. Get dishonorably discharged. The end.
And cost the military money for court martial and such, not to mention if they do anything TOO stupid then they get sent to prison, military prison which the military has to pay for.