I hate to burst their bubble for them, but if they do start to monitor traffic then it will simply get encrypted. This is one arms race that ISPs simply can't win.

If all of the governments of the world put pressure on MS to make Windows detect and stop this kind of thing, people will switch operating systems to something that allows it.

There's always another way.

If they see you've downloaded something, you could just say my router is left open and someone use it to download withiut my knowledge, what can they do?