How much of a military presence do we really need, in order to enforce regulations over shipping traffic though? Surveillance by spotter planes / drones, combined with the threat of legal action against the ship's owners, ought to deter all but the most hardcore bastards.
For them, in theory, a rare single cruise missile from Norad ought to suffice. Even then, you could start with a warning shot, and bill the ship's owner for the missile.
For more complicated missions, we could fly out a small inspection or police team in a flying boat. Instead of relying on arrays of 20cm cannons for protection, they would depend on the above mentioned system (which is similar to the Norad system already in service).
For them, in theory, a rare single cruise missile from Norad ought to suffice. Even then, you could start with a warning shot, and bill the ship's owner for the missile.
For more complicated missions, we could fly out a small inspection or police team in a flying boat. Instead of relying on arrays of 20cm cannons for protection, they would depend on the above mentioned system (which is similar to the Norad system already in service).