Follow the money: well, it is a possible method of approaching the truth. In this case, let us say for the sake of argument that there are three factions within the army (the navy and air force are not considered important players and can be bought off in due course with a submarine or additional unneeded fighter planes).
The factions are: Prem’s people: deeply reactionary yellow shirt types (perhaps 25%), watermelons (pro-red shirt and in some cases pro-Thaksin) (again perhaps 25%) and the neutrals (50% or thereabouts). The fight going on between them is who will take the top position in the army once Anupong retires (which is due to be in October, as I recall).
The prizes of this, not to mention the status and getting to stand in number one positions at official ceremonies and the like, include the Prem plan to establish a new armoured division in Korat (with its multi-billion baht plan to buy tanks) and other high profile procurement opportunities. These procurement opportunities are, of course, according to this argument, primarily opportunities for whoever is in charge of the army to put most of the money in their own pockets and the pockets of their supporters.
Currently, the three factions have not been able to reach an agreement and, apparently, are reinforcing their troops in Bankgok. At some stage, probably this week or next weekend, a coup will be launched on the pretext that the current government cannot keep order and, if no agreement among the factions has been reached by that time, then there will be considerable bloodshed in the city as the rivals fight it out.
Another rumour has it that the truck full of weapons now in the hands of the red shirts was in fact deliberately left behind by watermelons to help them protect themselves. In this case, I usually incline towards the cock-up rather than conspiracy theory of history, especially when the military (of any country) is involved. Military formations are not designed to be learning organizations.