Originally Posted by
Steve M
Just detach the keyboard and you won't have a problem. You can even watch it during taxi and takeoff.
This is your best bet.
Large electronics such as laptops are prohibited during critical phases of flight (below 10,000 feet) when the need for an evacuation is most likely (as slim as it may be). A large device could create a trip hazard or otherwise impede egress. This is the same reason they are not permitted in seatback pockets. I don't have the specific example but most rules like this are "written in blood," which means it has happened before.
-J.