my knowledge is that its a severe breach of consumer rights as well as the right to privacy of all users of their service. And from my knowledge all you do in game is click and it sends a message to the server where you have clicked and the server displays back to your computer the animations of your character. As for browsing their website eg the forums, thats just displaying a simple web forum that up dates constantly.
on the contrary its illegal, however many scar scripters take the precaution to rename their scripts so that they appear as 'windows media player' on the taskbar. Though i do not believe this is necessary.