For this question who can answer?
In the fighting along the border of Cambodian and Thai, both sides always accused each other since the border conflict happened after Cambodian register Preah Vihear temple into the world heritage list of UNESCO.
For me, I believe that all the fighting may happen by Thai first. The reason that I can say like this is depend on my own simple understanding.
In a dispute between two persons, each person will say they are right, this is the human being phenomenon, but only the third person can say which person is right and another is wrong depend on evident and some …, and the border conflict between Thai and Cambodia is look the same.
In order to show the public which side is wrong and right Cambodia propose to have a neutral observer to the conflict area, but Thai always say no, therefore this is my own simple understanding.