What is so infuriating is the inconsistencies without any apparent logic.
Fopr example in the UK (and on UK airlines) the message is clear that electronic devices are to remain OFF until safely inside the terminal building.
In the US the cabin crew generally PA (in a weary tone) turning off the runway onto the taxiway that "Those that must can turn yer phones back on now".
In most planes my Ipad has to be off below 10,000 ft. In my plane I'd get lost if it was off.
I've flown with plenty of flight instructors who keep their Ipads and phones fully GSM enabled and who have been emailing, texting and receiveing weather updates with them.