Scott, it's possible that the airlines simplify their explanations of the hazards.
As an aircraft instrument and electrical technician I can tell you of at least one aircraft type (a business class plane, the Falcon 20F) where I can change the fuel state or nav heading (gyro compass) from the cabin with just some cheap electronics.

The fuel state can only be affected with the aircraft on the ground, the nav state can be affected anytime gear and flaps are down. It won't work with good quality electronics...only cheap stuff that bleeds RF like a stuck pig.

Not really a big danger in most cases...but who needs distractions during critical flight phases?
Keeping the pax (who are mostly just cattle and have no idea what is going on in a plane) aware of their surroundings is vitaly important...and easier to explain than radiant RF fields and induced EMF.

In truth, it shouldn't be possible to affect a commercial airliner...they are tested against this after all. The trouble is that no one can test against every combination of devices and their configuration.