system
Given the following post, respond as if you're commenting on Reddit:
human
Realistically, how dangerous is using a mobile phone on a plane?

I was just on a flight, and the stewardesses were insistent that every phone, laptop and even mp3 player were turned off and put away before we began taxiing out for takeoff. I fly quite often, but this time the rules seemed to have been tightened up a lot compared to other occasions.

With time to kill and nothing to occupy my brain, I got wondering about what damage phone use could do on a plane... So, I thought I'd ask science!
gpt
There's probably no danger at all from a properly manufactured and licensed piece of hardware in good working order (like a consumer cell phone or laptop, manufactured to US FCC standards)

BUT

There could easily be some piece of hardware that DOES cause interference with the avionics. You don't want to find that out when you are taking off or landing! If something goes wrong at 30,000ft when they tell you it's ok to turn things on, there's a lot of time before the plane falls out of the sky. They can just come over the intercom and say "Somebody turned something on that broke the plane. TURN IT BACK OFF". If you're 100ft above the ground when that happens, you die.

It's a blanket policy, and it makes sense. It's easy and reasonable for a flight attendant to make sure everything is turned off. Yes, your Kindle probably won't make the plane crash, but if your kindle is ok, somebody else will think his tablet is ok, and then somebody else has a laptop, and next thing you know somebody has a radio jamming device and nobody tells him to turn it off.