I'd go so far as to say that there is no such thing as bandwidth theft.
That's not to say that bandwidth doesn't cost, but that the protocols, the servers, the configuration... all the tools you need to prevent access exist. If you don't use the tools then you have no-one to blame but yourself.
So if I leave my bag on the back of my chair in a crowded pub, enabling you to take it, that's not theft because I could have put the bag under the table where you couldn't get to it?
So if I leave my bag on the back of my chair in a crowded pub, enabling you to take it, that's not theft because I could have put the bag under the table where you couldn't get to it?