Several pages back I mentioned the 1993 WTC bomber who made a trial run using a fake identity.
Here is some more information on this:
Philippine Airlines Flight 434 - Wikipedia, the free encyclopedia
(For you who don't want to click: Ramzi Yousef checks in, using a fake ID, on a one-stop flight to Japan, A -> B -> Japan. From point A to point B he arranges a bomb to explode the centre fuel tank. He departs at point B. During the flight to Japan the bomb explodes but doesn't penetrate the fuel tank [different model of aircraft]. Philippine police finds out the fake ID is really Mr Bomber and raids his appartment. Damning evidence of foul play, and Mr Bomber ends up in US prison. Plan was to blow up about 12 US airliners simultaneously.)
Now, this has to do with the terrorist angle of this missing mystery as this COULD have been a repeat of the above. Some people questioned why terrorists would choose a Malaysian airline... simple answer is "convenience". IF terrorists did this (AND WE DO NOT KNOW THAT YET) they might just have chosen this flight for plain convenience. Nothing to do with Malaysia or even China for that matter. Just as in the case with the Philippine airline.
But, to debunk my theory so noone believes it too much, remember that it would be plenty foolish to copy a previous trial run. I'm sure intelligence services aren't THAT easily fooled.