Auntie - presumably you're referring to those Class F advisory routes in which separation is provided between participating IFR traffic only? In which VFR flight is also permitted, but which requires no RT contact with you nor clearance from you?
Class F ADRs are very far from being Class A airways; sure good airmanship would suggest that VFR traffic should give aircraft flying in ADRs a wide berth - but don't expect a military fast jet under VFR crossing behind an airliner in an ADR to manoeuvre to pass 5 miles behind it.......