Just to add my non-BA four penneth worth ... the issue of turning off electronic devices (including Kindles) is very much not BA-specific: most (decent) airlines have exactly the same policy.

I was recently on a KLM flight, at the "approach" stage when pax had been instructed to turn their things off. I was in a window seat reading a book - a good, old-fashioned paperback. The bloke in the aisle seat (middle was empty) decided that, if I could read my paperback, then he could read his Kindle. The purser disagreed and came and told him - quite shaply - to turn it off. He refused, pointing to me as an example of someone who would be 'equally distracted'. The purser smiled, looked around, and then explained that, if he didn't turn it off he would be suitably greeted at AMS by several hefty policemen. He also pointed out that 'the gentleman by the window' was not breaking any rules - and, incidentally, how do you turn off a paperback? The guy looked disdainfully at me, snorted, then turned it off and stowed it!

-- Henry