My personal theory is that is slows down the line so they don't have to work as hard

One of these days I'd like to walk thru wearing only a jockstrap and see if I get picked for a random wand search.

I am in sales and often carry various sorts of non-computer related electronics on the plane. Same old story, I take it out of the bag, put it in the machine, the belt stops, someone says "bag check", it comes out, they take it to another table, call over a supervisor and all stare at it like cavemen who just discovered fire.

Then they ask me "what is it", I tell them, they don't understand, they say "turn it on", I do, they say "OK."