In Canada the process usually goes like this: first check is by the Lead Greeter, whose job appears to be to direct you to the Priority Cattle or Normal Cattle line. Second check is by the Second Greeter, whose job appears to be to make sure that during the preceeding three yard walk you actually arrived at the correct line. The third check is by the Stuffer, whose job is to stuff your stuff into the x-ray machine. The Peeper doesn't usually need to check the BP, but if s/he spots something that requires a sniff, the Sniffer carries out the fourth BP check and retains the BP while s/he does the swab 'n sniff. So in the normal course of events I think that adds up to four checks in about 7 or 8 yards.

I've sometimes seen one or two additional extraneous people involved in the process. On one occasion I asked why the CATSA people outnumbered the passengers, and after receiving a sneer that said, "Why would you ask such a dumb, none-of-your-business question, I got a one-word answer: "Training".