Certainly could have avoided all this if he just bought a cell phone and paid month-to-month, or pay as you go... But no, it's the service provider's fault for providing a (probably) free phone with the understanding that you would pay for their service for "x" months.
Now that that is out of the way, I think it would be a pretty good feature on the service provider's part (and may save them from going to a collecting agency), if they had some "x month freeze" option included in their contracts (or even better, charge $20 to have the feature), where you were allowed to exercise the option once during the contract, for up to "x" months, where you weren't provided service, and didn't have to pay for service.
Once "x" months were up, the contract continued (so if you had a 1 year left before you exercised the option, you still have 1 year left).
I'm sure everybody would love to have this option "just in case" and whatnot, and a lot of people, not just military personnel going on tour, could make good use of it, with no harm done to the company. Also, for people that don't manage their bank accounts well or the unexpected happens, this x months grace may allow service provider's to not have to go to a collection agency to recover funds from a rogue debtor.