Just curious, is a phone line or broadband connection the only thing needed to prevent the auditors from calling when you have multiple boxes? If so then I assume Dish just verifies all boxes have the same Caller ID or the same External IP address when connecting to Dish, but using Proxy servers or VoIP would allow multiple boxes in multiple locations to have the same Caller ID or External IP... so I'd assume any customer with multiple boxes would get audited at some point since there's no fool proof way to verify this any other way.
Also is it worth paying the $30/month or more for a phone line just to prevent the calls? Seems like it might be worth saving the cash on a POTS line for the inconvenience of calls from the auditors, given they're just once or twice a year.