I have just found this topic after asking the same question on the Sony PRS-505 part of the forum.
I will also be disappointed to have to turn my book off for take-off and landing. In these modern times, I find it strange that devices do not come stamped with ‘Air Safe’ or some other sticker FAA/BAA/etc approved to say that they are OK.
An it’s a puzzle on where do you drawn the line? Just because a device has an off switch, is it really off. My PDA has an off switch, but unless I hold it down for a long time, it only switches the screen off. And almost every flight I have taken over the last 5 years, there has been a phone start to ring or an SMS come in either just as the plane takes off, or as its 10 feet above the ground coming into land.
But are Boeing or Airbus really making planes which will crash because there is some very minor output from an ebook or similar device?
But as I say, where do you draw the line? My watch has a built in GPS receiver, an LCD display, so may admit signals – so this be barred. Or what about pocket calculators – is there really that much difference between them and ebook readers?