genxfrog,
Tell me who would be liable then if pax had their laptops, iPads and other what nots out whilst taking off and heaven forbid something happened, like a rejected take off requiring evacuation, tray tables are going to be down so evacuation time increases, or after take off you hit turbulence. where do you think those objects are going to go. Hence why they can only be used when the seatbelt sign is turned off.
I for one don't want a laptop hitting me in the back of the head because some idiot has it out because he has "important" business stuff to do which cant wait 5 mins
Theres more to it than just interference with the aircraft. and with the electronics off the are less likely to be used