Mad Jock,
You may be right about 19 seats (Can't think of anything under 10 tons and over 19 seats?)
Definitely you are wrong about a private aircraft over 10 tons (outside of a CP) we do this most days (we are an FBO with a full screening suite in our building). If you are being screened on private flights it can only be that you are :-
a/ In an airport where the FBO ramp is in a CP
b/ In Edinburgh where they screen you for no reason whatsoever.
PB