"As an avionics specialist I think that the issue is well overdone"
(Rumour has it that) an Australian aircraft, very recently, started to porpoise _in cruise_. A different autopilot was tried, with no improvement. The third autopilot was tried, also with no improvement. The crew discovered 3 kids all using Gameboys (or something of that nature) in the rear of the aircraft. They were asked to turn them off... No problems occurred thereafter.
I'm no avionics "expert", but my money's on the Gameboys causing the problem <img src="tongue.gif" border="0"> Odds or no odds, electronic devices shouldn't be ignored.
Rgds.. .Q.