I hope they aren't instituting the UAX approach from SFO where you have to show your BP about three times on the way from a shared gate reader to the aircraft.

I'd say it is at least 50% the pax fault; I have taken Horizon flights many times out of those SEA gates and unless you can't read or are drunk it would seem difficult to mess this up. Of course, the count should have revealed the problem, too.

By the way, OP, you already have middle of the summer up there?