Theoretical nonetheless however I'm sure the airlports would rather not leave it to chance. No different to the risk of mobile phones bringing a plane down. Things are changing now but again in sure people would ether not take the risk.
Does anyone know of any other airline where this is policy? Or supposed to be policy? At my local airport they say it during boarding at the gate and absolutely enforce it. I saw a Canadian guy go to use his phone during the walk to the aircraft and he looked surprised when asked to put down the phone. When I flew BA last week it was boarded vi an air bridge on both ends so no such message was conveyed.
I can't believe it's just EJ though?
Having worked there, and told people this for too long, I now find myself wondering if I'm going to be told off for having my phone on during the walk out to the plane as I use the app for boarding! So for nothing has been said so it must just be for making calls.