David
The problem is that from time to time well-meaning people do ask the CAA for a ruling on something. Sometimes the CAA responds but if it is anything controversial it tends to stay silent. If they were more forthcoming, a lot of this speculation would not be necessary. Was 123.45 ever authorised for air-air? It is allocated to some ground units.
But no matter what, some subjects will always be debated because the legislation is a mess.
FNG
"Commonplace" as a % of total flights no, but it happens occassionally in certain circumstances where people ask a PPL to take them somewhere, most likely to an overseas destination.
Mike Cross
Do you mean 21 (2) (a) (ii) (aa)...(ee) ? That appears to say that a PPL can authorise a passenger to do the radio. However (aa) through to (ee) are ALL required but under (bb) the radio operator would be OK if assisting with "safety or navigation".