You agree to a license agreement when you take the TV, since it’s essentially being leased to you for free under specific conditions, and in that process, you give them a credit card and authorize them to charge you $500 if you break the agreement (or lose/break it, I imagine). I’m sure it can be jailbroken, but doing that in a way that cannot be detected is much much harder.

Not to mention, it would essentially be theft. It’s a freely made agreement. If you don’t like the terms, the correct thing to do is to simply not make the agreement, not to agree to it and then immediately renege on your end of the deal. If you break the agreement and essentially con them into giving you a free TV that they paid for, they’re absolutely going to sue you, and they’ll win.