You can always go back to wishing for simple out of Hitech.
Let them have their 2 week free access to all rides then, or instead, a new kind of account where they get only a spit9 or 109 G2 or A6m unlimited forever. Don't give them more options then that and you won't get slumming by vets canceling their accounts. And those three planes will not make anyone into a L33T since everyone else will have access to late war rides. Those are pretty simple rides at a minimum to learn and stay alive, if the person engages the vets for advice and decides to put in the effort. Otherwise, those rides will be here waiting for them whenever they remember the game is out there. Let them change to one of the other two each tour, and no activity for a tour on the account, it auto deletes. When they come back around months later, they make a new account.
Got the impression accounts like that are a pain to support the database from something Skuzzy said years ago. Still, If only those three rides are available, you won't get slumming for the GV game or long slow flights in the moonlight by previous vet strat runners who hate Hitech. At the minimum, you will have some "looky loos" to harvest knowing what the three rides are 15 seconds after your first merge. Be funny seeing all the spit9 being used as vets alt account so they can change country at will. At least it won't be vets changing at will upping perk rides.
If you complicate this it won't work.....though the last few times I've seen some thing like this thrown out there, the complication looked like a laundry list of what people would accpet at a minimum themselves to cancel their accounts and keep playing free with a reduced ride menu.