They already covered themselves in the TOS - black & white, it's ironclad. And there's a pretty consistent track record and precedent of courts ruling in favor of business with regards to devices and software that enable the stealing of goods and services.
You're referring to the music and movie industry. And yes, you're correct in that matter, although it took a while for the pirating market to take a big blow. However, it's still going strong.
As for tethering? It's an unknown how this will play out because there hasn't been a lawsuit submitted by any carrier to a consumer for illegal tethering. If verizon knows who is doing it RIGHT NOW, then why isn't anyone getting charged for the usage? Perhaps its because their TOS isn't so ironclad afterall. Or, they can't legally track what apps people are using without breaking privacy laws.
Trust me, there is a loophole.