In the case of cap ships why not have licenses that get lost when your vessel is destroyed? Not so much a restriction on how many you can own, but more you must have one. Attach the 'Cannot launch without radar" code to them. In cases of not having enough on board, there could be a service to replace lost licenses. That would be incentive to keep at least that extra amount on board. All license will be availible everywhere.
(Note these numbers are being based on Disco as it currently stands)
Loose your gunship or basic transport (1000-2500 cargo) it costs 15 million to buy the required license for upkeep.
Loose your Cruiser or high end transport it costs 35 million for the upkeep.
Loose your Battle cruiser or liner, 50 million.
Loose your Battleship 100 million.
Thoughts even thou they spin this thread off topic?