People are constantly bombarded with seemingly unnecessary warnings. I frequently assume that these warnings are to insulate a company from legal trouble and not really to protect me. This might be an American perspective.
Warning fatigue is a real concern, and requiring people to watch videos on the internet should not be a prerequisite for adequate safety.
I've definitely noticed a proliferation of warning notices and signs in the US (and I don't just mean the Californian chemical hazard warnings in the most bizarre/unavoidable locations like a jet bridge), with the really important ones usually reiterated by a human standing next to them, continuously shouting the same instruction, apparently because people don't seem to take them seriously otherwise.
It’s always been an American impulse to resist authority and think for yourself. That is generally admirable. Then at some point the “think for yourself” part got tossed out, and people disobey instructions for the sake of it.
It’s not that hard to follow instructions. There aren’t that many, and almost all flights have the exact same ones. If you don’t want to learn about getting tossed around like a rag doll at 40k feet that’s fine, just do what the crew tells you to do and you’ll be ok.
It's not "known nonsense", but not for the reason you think. There's a small risk of your phone connecting to some random carrier located in whatever country you're currently flying over. For some smaller / third-world countries, this can be quite expensive, cents-per-megabyte isn't unheard of.
Every time this is brought up people come out of the woodworks with post-hoc rationale for this rule that has no basis in historical fact. This comment is good example.
Why would the FAA and other aviation regulatory agencies care about your phone bill?
I completely agree on GPs statement being absurd post-hoc rationale, but interestingly, this rule is actually coming from the FCC, not the FAA [1], with the FAA only indicating support for it [2].
The motivation is supposedly cellphones at high altitudes interfering with far-away cell towers that are reusing the same frequency at a distance that would normally make interference very unlikely, given the radio horizon and everything.
I highly doubt that that would still be an issue modern networks couldn't handle (also given that most other countries don't have a corresponding law on their books, as far as I know), yet here we are.
It's not the reason the rule was implemented, it's not something the FAA cares about, but this doesn't change the fact that it's still a good idea in some cases, rule or no rule.
By that logic, many more things ought to be declared illegal by completely unrelated regulatory bodies. It would be a bit like the FDA banning gambling, or the SEC reinstating prohibition.
It may still be a good idea because of battery but basically no one cares. Contra early days of smartphones when there near altercations with passengers responding to one last email after the doors closed.
Something interesting I’ve seen on my recent domestic United flight, which I don’t think I’ve seen before.
While the flight safety video was being played, a male flight attendant was walking through the cabin and actively telling people with headphones on (connected to their own device), to take them off and listen to the safety video. It wasn’t a recommendation though, he would wait until the person complied and would then continue down the aisle.
I didn’t have any headphones on. At first it felt a little bit overboard, but with events like this turbulence happening, I can see the need for it.