So, earlier this morning, I'm cooling my heels in the Maple Leaf Lounge at YUL, waiting for United Express to ORD. Boarding is at 11:30 (for a 12pm flight), so at 11:29 I head to the washroom, figuring I'll stroll down to the gate and board at 11:40 or so.

As I open the door to the washroom, the lounge guardian comes on the PA: "Are there any passengers here for United flight XXXX? You need to go to the gate right now; your flight is departing!"

"What the...?" I think to myself, as I'm running.

Onboard, the FA explains that the aircraft got in early. And if the flight crew is on the ground more than 90 minutes, they have to go through customs... so they decided to leave 15 minutes early instead. Somewhat to the surprise of the F pax in the lounge.

Anybody run into this before? I'm curious how often it happens.