Heathrow Director,
that is my point exactly.
If, after a couple of hideous flights with yak yak yak all the time, people decide to do something about it, there may be lots of these devices on board.
Mr Clever Cloggs from Acacia Avenue will no doubt think one little jammer won't harm, and maybe he is right. But what about 5, 10 or 50. You cannot search people for them and telling them they are not to be used is likely to be ignored when Mr Cloggs thinks you are only saying that so you can ruin his peace and quiet and therefore make more profit.
I am not debating the rights and wrongs of phones on board, just the bit about jammers and their effect on aircraft systems.