Earlier quoted context omitted.
Yes, anybody should be able to do that with no legal consequences. If you don't want to give people access to your network, don't provide them with a fucking port and cable explicitly designed for doing so.
Come on now, you really think people should be able to unplug cables anywhere they go? This could have major consequences at a hospital. Edit: Completely agree Ska, no excuse for making it this easy. I'm just pointing out that just because it's easy to pick a lock or unplug some wires to MiTM doesn't mean it should be legal.
If your security model relies on this, though, you have failed. Period.
It is maybe a little fuzzier in a hotel (should I be able to stream content to the TV from my device instead of paying you extra for a movie?) but similar applies.