[jameshart]

Arbitrary deadlines like this are heuristics that we give to systems or people who don't have realtime access to the full picture so they can make decisions that are probably, on average, more likely right than wrong. The human checkin clerk can, at their discretion, call the gate and see if boarding is delayed, or find out how the security lines look, gathering additional information to make a decision, but the one hour deadline is a rule of thumb that they can use to make an initial call. But even with the additional discretion they have, they are still guessing whether the rules are worth bending for this passenger, what the real value to the airline is of getting that customer on this flight or bumping them to a later one.

A computer replacement that doesn't have any additional data, and isn't programmed with the discretion to make those calls to find out additional information, is going to just make the call that checkin is closed. It is probably an inferior solution to the human.

A computer replacement that has information about current security wait times, gate status, as well as information about all other flights, the location of the inbound plane, the estimated lifetime value of the customer standing in front of the kiosk, what competing airlines are doing, and the exact current company financials, can put all that data together to make far better decisions than the human checkin clerk could, in the best interests of the airline, and it doesn't need to be given arbitrary rules like 'turn people away if they show up 59 minutes before scheduled departure'.