I guess they would need some kind of special shite to do that tho, as dynamic IP adress on regular routers is apparently just this:
"You’ll read most everywhere that a dynamic IP address can change “at any time.” True, but not likely. The fact is, even if you have a dynamic IP address it’s possible that it won’t change for months on end."
From here: http://whatismyipaddress.com/dynamic-static
Also, wouldn’t having a constantly changing IP adress make connecting to servers almost impossible, or at the very least highly impractical, as you would lose connection for a split second all the time?