Originally Posted by Dan Burgess
Indeed, online check-in is a godsend for this trick, as the 10-minute rule no longer applies.
As nsx said, the 10-minute rule will apply.
A passenger must be "present and available" to board 10-minute prior to departure time, or your reservation will be subject to cancellation.
I think they normally wait until the plane is loaded but I'm not sure if they have to.
How else would we know if you were missing?
If you are a connecting passenger on a "scheduled" connection and your flight is delayed, a decision is made whether or not we hold the plane. It depends on a lot of factors. (We are aware of who is connecting/how many we are expecting, and so forth.)