I'm playing around with the idea of setting up a website for pilots to register their drones on. Which would be open to any UAV system, not just multirotors. My idea is to simply issue a "license plate" sticker for your bird. That plate would be registered in a database and when your bird is found, the finder can check the site for your information. I see that someone has registered dronetag.com but so far isn't doing anything with it. And this would be worldwide. Not just the USA.