This is why flight attendants tend to keep their hands behind their back as you board a plane

The more you know.

There are a lot of things that confuse us about planes... For example, why on earth the window-shades need to be up for taking off and landing. Another thing you may have noticed that is that as you board or leave a plane, the flight attendants might keep their hands behind their back. Although this may just look like common courtesy, or just a formal, official posture to keep, but apparently there is an actual reason for this. The reason they do this is to keep count of the amount of people boarding and then exiting the plane, according to Indy100. At least one of the flight attendants will be holding a contraption similar to the ones that used to come free with Lynx that lads would use for keeping track of how many girls would smile at them. So there you have it. https://vimeo.com/44648818