simply put: prevent the equipping of high end gear before the player as reached the proper tier clearance
so...
T1 players that haven't been granted T2 clearance can only equip 0*-2*
T2 players without T3 clearance can equip 0*-4* only
T3 clearance allows all equipment currently in the game at the time of this posting
note: this does not prevent the trading of high end equipment whether it's a friend gifting to another that doesnt have the clearance or a merchant player selling to a new player that is rolling in the energy