This is all so stupid. Your electronic devices will not harm the aircraft in any way. There would be planes falling out off the sky left and right if they did. Do any of you really think the aircraft manufacturers and the regulatory agencies trust passengers to turn off their devices? Of course not. Therefore any sensitive equipment is sheielded from any interference. It's just a leftover rule from the early days that the old wind-bags at airlines like AA and UA still gripe about.