Did you sign a piece of paper when you had your system installed? On the back is the lease agreement. Did you buy your system at best buy? You signed the electronic pad which displayed the lease agreement.
You know that EULA you clicked "I agree" to a couple of weeks ago and installed the software without reading all 27 pages?
Good news! due to your implicit agreement, we get to place your entire family into indentured servitude! Your 10 year term begins tomorrow. Pack up! Its off to Antarctica to mine ice!
A $480 fee being conveniently placed where 99% of the population doesnt bother to read it is inappropriate. If you want to levy that sort of money, either a voice recording of the directv rep telling you about the fee and you saying "I agree!", or a big piece of paper with the fee amounts in 24 point safety orange with your signature on it would be more appropriate.
Being charged $480 for canceling service after a month if the service is inadequate and directv doesnt make it right for you is a ridiculous amount of money.
As an aside, most cell phone contract cancellation feels is $200 if you cancel up front, Dish networks appears to be $320 if you cancel the first month.
Directv is THE LEADER in high cancellation fees!!!