I usually have mine tucked in my backpack through the scanner and it's never been pulled for inspection. I know many people have gone round and round with flight attendants over when to turn them on and off but I've never had anybody say a thing to me about my Kindle. I usually just browse the sky auction magazine thing on take-off until I hear the ding and then I pull the Kindle out. I've never had a flight attendant ask me to put it away for landing, so I never have.
Best advice
DO NOT TUCK IT INTO THE SEATBACK POCKET AND THEN LEAVE IT!
sorry. It's just we see that all the time on the boards. Apparently it's really easy to do.
Have a great trip.