For those waxing poetic about Lithium Ion batteries, you have not traveled in an aircraft in the last 5 years that has not had tens of lithium ion batteries in the aircraft hold and passenger cabin. Even the Cathay Pacific rules upthread would allow 2 extended life laptop batteries (random packed by pax with cables and USB drives) in their checked bags - so in a widebody you have the potential for several hundred of these. And there HAVE been fires in the passenger cabin due to laptop fails.
Now as also said you have to come up with a practical way that a fire in the hold that would immediately trigger an alarm in the cockpit, could stop ACARS, SSR transponder and the three independent VHF radios in the short period of a simple change of frequency usually by selecting the 'other box' - without any distress call from the crew.
This would be a really severe fire.
Yet the aircraft flew a zigzag course across the Malaysian peninsula around the top of Indonesia and then flew South for another ~6 hours with continuous power to the SATCOM equipment.
So apply a modicum of logic to these theories.
I also second the idea of moving the detailed discussion on 'safety of LiIon Batteries' to the Tech Log in a new thread as it seems to excite 'heated reactions'
in some posters here.