I always have wondered if inventory control is a person or a computer. For example, when there are 30 empty C seats on a Trans A or P flight, with a wait list, and it's a few months or weeks or days out, do computers make sweeps to check inventory? Or does a person do this by schedule from time to time? Would an inventory/upgrade check be prompted by a load factor that is higher or lower? Anybody know this?

And of course I know the gate agent does a lot of this at the airport, but I mean in advance. Thx!