Because you need to let Directv know EXACTLY where the receivers are located so you get the correct local channels. They are not allowed to provide locals that are not in your DMA unless: They are significantly viewed ones, or you have an waiver for the reception of distant nets. It may not be "illegal" like Scott G. says but it's against FCC rules and you could and should be shut down if you give Directv a phony address for different locals or RSN's. If you want another markets locals rather than your own, simple pack up the dish, receiver and your belongings and physically move to a new home, pretty easy isn't it. Both providers need to clamp down on this sort of dishonest activity as it deprives the local station of advertising revenue in YOUR DMA not some other market. Spotbeams help that a bit by limiting choices to a few hundred miles of said "moved" to market.