Flight attendants pretty much always stand with their hands behind their backs when welcoming passengers on board the aircraft.
But this particular stance has nothing to do with security or hygiene – it’s actually part of a numbers game. Before take-off flight attendant is required to count passengers. Counting the lead or at the entrance or in the cabin, when everything is already seated.
A courtesy rule that actually hides a much more pragmatic goal: in fact, the flight crew adopts this behavior in order not to attract attention when counting passengers. Indeed, you certainly did not know that a small manual counter is in their hands.
The counting of passengers on board the aircraft by hostesses and stewards is a security measure related to the international regulation of air transport. This stipulates that governments, airport operators, and airlines must guarantee that a passenger who has presented his boarding pass to boarding control will no longer be able to leave the circuit leading him to the plane.
As the procedure was left open to interpretation, it appeared that the most effective method to date was to count the passengers on board the aircraft before take-off. If this count shows any anomaly, the takeoff is delayed the time to perform all the necessary checks.
From AWM:
After the flight attendant in charge of counting finished their count at the front of the plane, they repeated the process by walking down the aisle and re-counting every passenger. This process can be a bit tedious, but it is an essential part of the flight plan because the airline cannot afford to let someone get on the plane who didn’t purchase a ticket.
But why do flight attendants have to count the passengers with their hands behind their backs? While every airline is different, it seems that flight attendants simply do not want to draw too much attention to what they are doing lest a passenger interrupts their flow or disturbs the process in some way.
Now, the next time you get on a plane and you see a flight attendant with their hands behind their back, you’ll know that they’re not up to anything sinister. They’re simply counting the passengers onboard to make sure no one snuck on who wasn’t supposed to be on the flight.
Source: AWM