A question about online check-in
I always thought that checking-in was the airline's way of knowing someone was at the airport and not stuck in traffic on their way to the airport.
If someone checks-in online and does get stuck in traffic, how long is it before the airline assumes that person is not going to make it and re-allocates their seat ?
Also, what if so many passengers check-in online that the flight is considered full even before check-in opens ?
Does someone that has not checked-in online but has arrived in pleny of time get told the flight is full ?