I think Tesla Motors has better things to do than prioritize the order of firmware updates to users playing with the Nav with absolutely zero assurance that those users will provide any feedback. That's a total waste of their time to prioritize based on Nav routes like that. There might be an order within the autopilot cars, but I seriously doubt it's based on "people who put in long trips into their nav, even if they're just playing around."
An easy test would be for any other AP car owner to do the same, and see if they're updated as quickly. Of course, if they are, that doesn't prove the theory (since AP cars are being updated hourly). We'd need people to do the same Nav routing, and NOT be updated the same day. Still, that doesn't prove much, so I stick to my assertion that Nav routing has no factor on firmware update priority. None.