Well, have always had all 6 STB's connected to phone line for 8 years, then two of them to broadband. There have never been any problems with any of the STB's connection to Dish. I monitor that and frequently test the lines via the menus. Never heard from audit team, except that when I installed my 5th box many years ago, the installer was told to call auditing, as that was the only way Dish would authorize the box. The box was authorized, but Auditing told the installer to tell me that I had to have all my boxes connected to a phone line AT ALL TIMES, or they would shut down the boxes! Since day one of my first install, this has always been the case, so this requirement was no problem.
Then, one day about 8 months ago, Auditing--now renamed Signal Integrity--called and wanted me to read off all the numbers on my boxes, I kept telling him this was odd because I know that all my boxes had been reporting to Dish. He never addressed that inquisitive statement, but he was VERY polite, and explained that there could be no interruption of our phone call and wanted me to be certain that my cordless phone had sufficient battery power for the remainder of the call.
Any way, I read all the numbers. He was quite pleasant throughout the entire call. After satisfying him with the correct numbers, he then said a polite thank you, and I wished him well. I haven't heard from them since, but it was clear that even though my boxes were in contact with Dish, Dish called for an audit, anyway.
My experience was quite positive. However, I have no doubt that others may have been poorly treated. I think the key is ALL BOXES connected to phone line or broadband AT ALL TIMES, and one can go quite a long time without ever hearing from Signal Integrity.