I am very much inclined to support your hypothesis. The idiot Generals have made some incredibly dumb moves in the past weeks, seriously bringing into question their ability to manage the economy. Thaksin may have made himself rich, but he was bringing others along with him and apparently making enemies among the sex and drug economy. Incidents such as this seem likely to distract attention from the problems of the coup leadership and strengthen the Army's support.
General Sonthi came to power promising restraint and dialogue in dealing with the terrorists in the south. I'm not sure more bombings this soon would strengthen his position.