Lastjustice wrote:whats the difference between using the matrix and activating it ?
The Primes didn't just use their bodies to seal the matrix of leadership, they put their very essense into it as the ultimate security. No one could use the matrix till it was earned. Once someone kept it and shown worthy it would reform. Which was what the Fallen was waiting for to happen. (since he likely had enough knowledge to know he wasn't going ever get his brother's approval on his own.)
When Sam has his near death experience he has the allspark in his head, and so the two artifacts are comunicating with each other. He proven worthy of a leader as he was willing to die for Optimus as he was for him. The knowledge of the all spark was then removed from Sam's head and into the matrix...which in turn was given to Optimus Prime when Sam used it to revive him. Which in the Prime's crazy vision was his destiny..(or that's what they tell all the people who have visions of them hehe.)
Once the Matrix was activated , the Fallen could then steal it. Given Optimus was there to reclaim it the Primes likely let his actions stand. Which we see Optimus with the Matrix in DotM.
well im sorry but thst jsut speculation
its a pretty shit defence system, if its found by someone worthy, then anyone can use it