score:4
The way it works is like this.
An airline leases gates from an airport, and the airline is responsible for deciding which gate a particular flight uses. Usually it is planned and decided hours (if not days) in advance, and there is a daily pattern of usage, so the same daily flight will usually depart from the same gate.
When an aircraft lands they call "ramp controller" to find out what gate they supposed to be at. Ramp control is operated by the airlines. They don't approve movement of aircraft, they just decide which gate the planes for their airline go to. When they know what gate they are going to the planes tell the "ground controller" who works for the airport and actually controls the movement of planes, and who gives them clearance to get to the gate they have asked for. (Planes almost always know roughly which part of the airport their gate will be, so the ground controller will get them moving in the right direction while they are finding out their exact gates.)
Possible scenarios: