Pretty sure Comcast as been caught doing that too -- probably all ISPs have done it. Reminds me of AT&T getting caught/busted/whatever charging some kind of fee which was supposed to have stopped for many, many years. Sometimes when this stuff happens it is simply bad procedures or incompetence, but I wouldn't be surprised if much if it is on purpose.
“Extinction is the rule. Survival is the exception.” -- Carl Sagan