Well, I know that there are many things possible. Legal, that is another story.
** Check you local and state laws**
DirectTV boxes DO NOT NEED to be plugged into phone lines. I never have in 7 years of having a box (or two).
At one point I was "borrowing" my in-laws signal. I had a box and a dish, they had a box and dish 100+ miles away. My receiver was on their account. There is NO WAY that DTV will know the location of a particular account box UNLESS IT IS PLUGGED INTO A PHONE LINE, and then it's only a maybe.
When you want to watch PPV, setup the purchase over the internet. It's just as easy and you don't need to drag a phone line to the dang receiver. The only thing that may be of use to have the phone cord plugged in is caller ID (if you have it... I don't waste the $4/month on CID).
There is no such thing as a "spot" beam, contrary to what DTV may tell you. I had my bill at another time go to my in-laws house in St Louis, but lived in Tulsa with my box. I got all the STL programming in Tulsa. The tech told me "the STL channels are on spot and will not work elsewhere".... BS.
I don't know if there is a limit to the number of receivers on an account. I know that 4 is no problem since they now offer (4) receivers in a package. HDTV DTV still works the same, the difference is that you need an oval dish to point at multiple satillites. It's a bit trickier to set up, but if you've ever had DISH 500 it's the same setup.
I have moved with my DTV over 7 times and have yet to have a tech come set it up for me. It's not hard to do, sometimes it can be time consuming since you have to know about what direction the sat is in, then systematically sweep the dish until the transponder under "SETUP" goes nuts.
A word of caution on HughesNet.... I have not been exactly impressed when comparing it to cable or DSL. There are many websites that I could not access as the ping return from the website was not in sufficient time. Luckily, MyST.com was not one of those sites. The speed is also not eye-popping fast. It may have been my laptop for part of it, but not all as another laptop and a desktop connected to the router all couldn't access those particular sites.
I have been generally happy with DTV since I got it in Jan. 2000. I'm not happy that they keep raising rates and that I can only get "local" channels out of either NY or Los Angeles (I'm in North East Arkansas for crying out loud... Memphis and Little Rock have their local channels on DTV and both are only 1 hour away... if I had cable, I could get both!!). Thinking of "moving back" to STL if you know what I mean....
BTW, if anyone needs a DTV receiver, I have an older Hughes box that is not being used that I would be glad to sell off. Has a universal remote. I don't have a spare dish or LSB, but if you need a box, speak up.
Just my $.02.