From my background “Bodyguard” (BG) is used to identify the CPO that provides one-on-one protection for the principal, members of other security details associated with the task/contract (“P.E.S. – Personal Escort Section, S.A.P. – Security Advance Party, C.A.T. – Counter Attack Team, R.S.T. – Residential Security Team) consist of CPOs, where some teams (e.g. RST) are sometimes augmented by less experienced/qualified security personnel.

The BG often has all the training the other CPOs have and has often got all of their experience as he has often “come up through the ranks”.

Of course there are always exceptions in the civilian marketplace and levels of training/experience/ability can vary a great deal.