You can snatch it away and, giggling, run off with it streaming behind you. And no one can stop you. 'course, you still have to file off the serial numbers, and probably mix it up with other ideas (stolen or not). But it can still be great fun to come to the point where you develop or twist that idea in the way that really works.
I've got an outline in the works that has no less than three ideas stolen and twisted to my ends.