If you don't write enough, it could be deemed "insufficient" content. Just post, and they will automatically tell you if there is anything wrong with your hub. I currently have "insufficient content" listed under an unpublished draft. They took off adsense till I could improve upon it.
Everything out there is protected, but content thievery is rampant. It's difficult to control. Don't worry about it, though. If someone ends up publishing it and making enough money off of it, the true test would be to prove who published it first.