AI drivers/gunners in wheeled vehicles would dismount seemingly without apparent reason then get back in, and often they get killed. Tank type vehicles doesn't seem to have this issue.  Example:  A tank team with M1A1 and M1128 MGS, the styrker crew would disembark randomly. I tried setVehicleLock "LOCKED"; in Server_BuyUnit.sqf, but it doesn't prevent AI from exiting the vehicle.