The showrunners don't want to get in trouble when armies of fans type in stuff from screencaps. It's like how cars in movies have fake license plate numbers and telephone numbers all start with 555.
Using a real phone number, license plate number, IP address, or physical address in a show/movie/song has the potential to provoke throngs of fans into malicious, or merely inconsiderate, actions -- prank calls, ping bombs, or simply visiting and not cleaning up after yourself (which is what led to the Goonies house closing: http://www.independent.co.uk/arts-entertainment/films/news/g... )
