Wasn’t there a movie some years ago with this as a plot device???
The guy in Casino Royale who was able to impersonate a tarmac worker to hijack a fuel truck to blow up a brand new plane. Thankfully James Bond was able to stop him.
I've noticed most of them are teams of 3-4. One of them says little or noting and usually just watches the scanner screen carefully. The others paw through luggage and prod the cattle through the chutes. The screen watcher is usually the brains of the outfit; the others are there for show (and paychecks).
They could be just as effective with half the number of people (or less), but then we wouldn't have the theatre and they wouldn't have the paychecks.