A precise definition of the term, "contact," with respect to contact with a law enforcement officer (or comparable authority figure) is needed for those of us who pack heat. And such definition, with helpful examples, we never have had.
My uninformed guesstimate is that anything more than a casual, "Good morning, officer" while passing by should be construed as "contact," to be on the conservative side. And it's always best to be on the conservative side.
If you are packing heat, it's probably best to inform the officer at the outset and invite the officer's response and direction rather than have the officer discover the presence of a firearm later, perhaps then becoming alerted, alarmed.... All that.
Plus, failure to notify is some kind of misdemeanor here in Nebraska.
So gently notifying the officer/agent at the very outset of any kind of contact is probably the best approach, either for CHP holders or ordinary constitutional carriers.
YMMV.