They want the phone line plugged in because with the box call in via the dish 1-800 number they do a caller ID check to make sure the box is really at your house and not at a friends house.
There is no way to turn off the caller id check as dish is paying for the call on there 1-800 line.
If you dont call it they charge you $5 more each month to pay for the Dish Auditing departmetns payroll so they can do randon calls each year to make sure the box is really at your house (you have to read things on the screen or box to verify).
All this becuase of some dis honest people out there sharing receiver, we have to plug in the receviers.
IMHO it's about lost revenue for Dish. I'm thinkin' there's some bean counter in accounting who figures that most people do some PPV and since you *can't* do PPV without a phone line, they'll get money out of you anyway. On the 622 you can't even use it until you plug in the line - my 508 hasn't been plugged into a phone line for 5 years (and I don't do PPV).