Originally Posted by
missamo80
They should check on boarding, but in practice I don't know of any airline in the US that does that as part of the boarding procedure. Alaska certainly doesn't.
Neil
Well the barcode scan is essentially a surrogate for that (assuming the passenger didn't switch BPs with somebody).
The problem is if there are multiple planes after the BP scan like in the SEA bus terminal gates where the OP was departing from. No reason they can't have a second BP scan at the door to the tarmac for validation.