But, historically, strongmen/chieftains have not had incredible trouble keeping their goons under control. Most threats from from palace coups not popular revolt. Most normal people in uncertain times like order and aren't going to flip the table on a system that gives them stability, food and shelter.

Grunts under coercion has a rich history that's still ongoing, but these sort of guards are those that would have both weapons and the guarded in their direct vicinity. I can't think of any historic example where this wasn't the loyalest of the loyal types.

Allied United is one of the larger security augmentation firms in the nation, which makes is harder. For example, my Alma mater was secured by Allied Universal as well as a dedicated PD because the dedicated PD didn't want to be bag check for a library when they have been dealing with real crime (eg. A comrade in their sister PD across town's was shot by the Boston marathon bombers).