I am not sure the 'send us a copy of your licence' would work. what could stop me 'borrowing' one?
why can't you set up a screening mechanism so there would be, in all the major areas, (UK; US; Oz; Sand, etc.) someone local who would verify the bona fides and allow access?
In the case of employees working for airlines with their own areas here, the local Mod would be able to confirm.