Bluetooth in the air
Some airlines allow the use of Bluetooth wherevere pax desire, some only while up in the air, and some don't allow it at all.
Phones and tablets until about a year or two ago would commonly come with a jack... so it was possible to use a wire to connect headphones to a device. Manufacturers seem to have now stopped that - so Bluetooth or some other radio-based communication mechanism is the only way to connect the 2 pieces of electronics. Equally it's now difficult to find headphones that come with a jack - many are Bluetooth-only
Are airlines saying "Bluetooth is forbidden always" just trying to tick a regulatory box knowing that this likely gets ignored and hoping it doesn't matter ? Apart from when things are going wrong, does the low range and power of a phone (in flight mode) broadcasting via Bluetooth really matter ? Are airlines and aviation regulators planning to find a way to square the reality of what pax want and expect (i.e. listen to music or watch a film during a flight) with what the rules say ?
I know there are always corner cases - e.g. flying through particularly difficult weather or something uncommon and problematic - but these scenarios are usually obvious and it's possible to get pax to change their behaviour on those occasions. I'd like to instead think about what should or will happen the rest of the time.