Originally Posted by
bocastephen
They are certainly airline "staff" (at LAX, EWR) - they are contractors hired by a single (or group of) airlines to check bags or direct customers to specific lines.
Some airports, like SEA, have staff who are airport-hired, who may help direct line traffic but don't generally bother with bags unless they see a size or quantity that exceed federal limits or won't fit in the x-ray.
I think that ignoring an "official" whether they are airport-based contractors/employees or airline-based contractors/employees, is something you should do carefully. If you get away with it ( walking by them muttering Icelandic) fine, but if they say something very clear that is an order like
"Sir, stop where you are and come back here and size your bag" and you ignore that, you are taking a good risk of having a bad travel day. If that person is angry/difficult/ annoying enough, they might drag someelse into it that has clear authority. And that person is very likely to side with the contractor/ employee at least on the point that you should have obeyed their orders.