Magnetic nano caches could certainly be a trackable cache. There could be a code on them with a log, and you could press a button on the app or put in the coordinates on the website. The map would now show a icon to indicate that the trackable cache has been placed. These trackable caches could only be picked up, discovered, and moved. They would have their own cache page, and the people who move it could maybe even add their own hint. The only problem is inaccurate coordinates. The solution to that is for the app to check that the gps signal is strong enough, and for the app to give the user tips to get better strength. In addition to that, the app could have a 3 minute timer before giving the user the coordinates, and can possibly average coordinates taken at different times. I know it’s not perfect, but I see it working. Make sure to let me know what you think.