I have no way of knowing if the journal was a plant or not. If it was in his handwriting, that would be easy to determine.
Under “adult supervision,” FSOs are reined in for their own safety, and the safety of their entourages who are also put in danger by foolish travel plans etc.
Reports are sent back to State, saying that so-and-so is a loose cannon, has “gone native,” is acting in a dangerous manner, etc.
An Ambassador Stevens would be recalled to Washington and read the riot act, or he would be replaced.
Without “adult supervision,” this is what happens.
If the MSM wasn’t so biased, this would be the focus of the reporting on the Stevens flap: He “went native,” traveled without security, and nobody at State reeled him back in.
CNN didn’t find the journal until 4 days later.
Plenty of time for the CIA (or KGB or...) to manufacturer a journal in handwriting that is close enough to Stevens handwriting to pass muster.