It is impossible to change it. The ESRB auto rates m to any online game due to the players. It is as easy as posting a link in the chat. Then we get into TF2's skins and such.
"Online content is not rated by the ESRB."
http://www.tf2items.com/profiles/76561197998389866
JoPereira sez: "It looks like Valve is doing some changes to prevent idling.. I'd say, do it at your own risk now"I don't know where he got that info, but it looks like your idling days are numbered.