Man, don't feel bad about not knowing the law on this. Thanks to all of you once again for what you're doing. Wish I could put my own in. But just like perchjerker said, keep it on the down low and keep the GPS numbers to yourself. Plenty of folks will see you fishing your brush anyway and eventually check it for themselves. Really can't blame them, it becomes public structure after it leaves your boat.
I'd be looking too ya know!