At LCY, boarding a British Airways flight means walking over the tarmac. The gate staff always announce the requirement to turn off mobile phones before leaving the terminal building.
Now for those passengers who have downloaded their boarding passes onto their phones do they:
(a) switch off the phone, then switch it on again 10 seconds later at the door of the aircraft, and wait a couple of minutes for the phone to boot-up in order to show the electronic boarding pass to the cabin crew greeter, or
(b) ignore the request, to be able to show their electronic boarding pass to the cabin crew 10 seconds later?
There seems to be a disconnect between the need to turn off mobile phones and the need to show electronic boarding passes at the aircraft door.