Albus is correct; it is all about conduct of flight not licencing!
Never had a problem in SP Ops in Cit II (C550) and C560 Encore with an FAA waiver (Form 4050)
Been ramped checked a few times in UK, France, and no issues and the checkers were only interested in; current pilot medical, IFR proficiency, CofA, a load statement showing t/o and land weight. Of course a check to make sure the flight is strictly private Ops, Both in N rego and VH rego aircraft.