formal evening dress: vest or no?

[CMcG]

With the greatest of repect to the Australian Army, military dress regulations have little to do with civilian Highland attire which is worn out of choice.

Thank goodness, eh? With no disrespect to the Australian Army Scottish Mess Dress White Jacket, it just isn't my style.

I posted that as an example to MoR's comment that a cummerbund is required by the mess kit regulations of some militaries.