Well that's all very well for the RYA to advise that and near the coast it's probably valid. We do have a handheld VHFand a ship's licence and an operator licence. However, it's range is pretty limited and I can sometimes get Oulton Broad Yacht Station from the mouth of Oulton Broad; but no further. (About a mile, Grace). Yes sometimes, over flat countryside it will work a lot further, but VHF is line-of-sight. That, together with the very limited coverage of a mobile, rather negates the advice.
I very much doubt that the Broads Patrols are manned other than in their working hours and I have tried several times to call them without success when a speeding boat rocks my sedate passage.
I can envisage the utter chaos that a group of happy chappies could cause on Ch16 if everyone followed the advice to carry an unlicensed VHF....
These are only my personal thoughts and I'm sorry to sound so negative but, really, nearly everyone can drive a boat if they have to.