Airlines employ teams, who look exactly into that (connections and potential misses). The look at the number of late incoming passengers that have a connection

Airlines employ teams, who look exactly into that (connections and potential misses). The look at the number of late incoming passengers that have a connection and make the following calculation : Is it cheaper for them to hold the connecting flight, or does it make more sense, financially, to rebook them? Including paying for hotel rooms and compensation. Sometimes they have an agent at the gate of the incoming flight whisking the connecting passengers to their flight. Here's another dirty secret to ponder: An airline may bump you even if there are free seats available. The reason being weight limits. It can be far more profitable to fly an additional container to Hong Kong then those three passengers with cheap economy class tickets. Even with the additional cost, which this incurs.