I have always been intrigued by these two phenomenons:

"Can Mr X if onboard let himself to be known to the crew"

Why? Every pax scans a boarding card before being allowed on the plane. How can it be uncertain that a pax is onboard or not?


The other phenomenon is the FA going through the cabin with a "clicker" or just counting pax. Same reason here, no pax can board unless beeped at boarding gate. How can it be uncertain how many pax are onboard?