And? You are going to run up to the cockpit and save us? Thank you, but...unrealistic.
It means you need to be attentive to the flight crew's instructions.
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My father is a commercial airline pilot, and he says that the main reason they want people to shut off electronics during takeoff and landing is so that people aren't using headphones during the most dangerous portions of the flight. If there is an emergency, passengers need to be able to hear and respond to instructions from the flight crew. According to him, no one is really concerned about consumer electronics causing problems with instruments, and he doesn't know why that explanation is always thrown out.
This is the same explanation I gave but people want to make light of it and think playing their dumb games is more important than shutting it off for 10 minutes.