We work this job 40 hours a week. We know when we're overstaffed and when we're understaffed. 5 is the magic number for most situations. I'd say 4 is the minimum but 5 gives you the safety margin for different-sex checks and the frequent times when you have to do several bag checks in a row. 5 keeps it going... an extra $13/h is worth it to keep airplanes from being delayed I think.