The word, "illegal" is key.
I don't know if you can technically say it is illegal to use your account in two different places at the same time but you are probably violating an implied agreement you have with DTV.
I, like many here, take my receivers on the road but, as long as I pay my bill I don't think DTV is making any great effort to limit my use. If they were really concerned, I think they would turn off my Distant Network access, since I have 5 receivers on my account. But, that would cost them $20 a month in revenue.
