[squeaky-clean]

The reason for that one I've heard from pilot friends is just that they want you upright and alert during takeoff and landing. I've been told to stop reading a book during a landing once. But imagine most of the flight crew don't want to deal with the potential fights from telling someone to put away a non-cellular device.

[blowski]

I seem to remember from "Cockpit Confidential" that things could get thrown around in the air during a bumpy landing, causing a risk of head injury to passengers. This includes books.

[cassianoleal]

I'm usually playing games, reading or watching videos during takeoff and landing. Nobody has ever told me not to. Why would I need to be alert? Do they think I'm not going to notice if the plane suddenly starts falling off the sky?

[Semaphor]

> want you upright and alert during takeoff

I’m great at sleeping, so I sometimes fall asleep during taxi and before takeoff. That was never an issue.

[vladvasiliu]

I'm the opposite, basically never sleep on a plane.

But I've seen many people asleep during landing and turbulence, and can't remember a single instance of the attendants even attempting to wake them up. They would go open the windows and taking care not to bother them.

[Semaphor]

I don’t envy you, my wife is the same, so those long flights (Germany <--> South Africa) are pretty hard on her. And yeah, as long as you are visibly belted, they don’t bother you.