Originally Posted by
respectable_man
Would the OP have been allowed to board if the bag was known not to be onboard?
(I understand the original BOS-YUL delay is WX, but it seems to me "second" delay is not since a ticket must have been exchanged to a valid itinerary.)
Generally not, but YMMV depending on the GA's mood and whether they've been made aware. I've been on lots of flights where my bag is not, but the airlines don't like to make a habit of doing it and don't like to broadcast it to the masses.