I have been told and showed where if somebody buys the L2 rank they can then log in with somebody else's account and use the restore purchases button to give them L2 rank, the three people I know that did this are Jooke, Sonidad, and Geooe.

Not even restoring purchase. Just attempt to buy L2.

The L2 being an in app purchase means it's Apple ID or google account specific. With your google or apple logged in, your device approves L2 on any account logged on in it. Unfortunate, but that's the thing with the programming.