Gosh, lots of intriguing & worrying new information on this thread today! I haven't yet read the fresh links posted, just wanted to respond to a couple of things.
Maybe the plane was expected to be tankered and was being flown at a distant target but wasn't in fact tankered and came down before getting there? - That is a VERY interesting theory, Doctrine.
Passengers' relatives: I would want to keep them away from the press, too, though I hope I'd be able to do it more tactfully. Look at what everyone all over the world is doing, including us here: theory after theory, question after question; misinformation being posted as fact. The relatives are going to be doing the same a thousandfold. Each statement, however irrelevant or unrealistic, is going to be examined in detail by the media - even more dead ends generated, even more mud in the water, probably innocent people being impugned by frightened, but ignorant, people. This is really the last thing the investigation needs.
Thai radar: Secondary (civilian) radar works by communicating with the aircraft. Primary (military) radar is proactive, in that it searches the sky and monitors objects reflecting its signal. Primary radar, therefore, monitors not just planes but flocks of birds, hot air balloons any other old rubbish in the sky.
It is not ridiculous that it would overlook an unexpected aircraft. (The Pearl Harbour invasion was missed because a fleet of US planes was expected at that time.) What usually happens is that primary radar sources check with secondary radar, as in "I've just seen something at XYZ co-ordinates, d'you know what that is?" Secondary: "No, how long has it been there?" Primary: "Not long, probably seagulls. Cheers."
Military radio operates on a different frequency from civil aviation. Commercial planes are not set up to receive military communications. For obvious reasons! This is why all the military installations report no contact with MH370; they don't have that capability.