I tend to agree with Beagle on this one. Mixing flying VMC and instrument nav on top and then trying to change that to VFR navigating with ground features is a risky business. Well broken clouds become not so well broken. Cloud thickness changes as do bases and tops as well as freezing levels.
Visibility below clouds change.
I knew a VFR pilot friend who flew to scotland with the intention of dropping back down through cloud having elected to fly VMC on top. His intention was to find a hole and continue to land VFR and in VMC. Amongst the densely packed clouds he found his hole and could see the ground below. Spiralling down he found himself surrounded by hills and poor vis in drizzle and much lower cloud than he imagined.
He saved himself by spiralling back up from whence he came. he then announced his predicament as a non IMCR pilot and was vectored to safety.
Even for experienced pilots changing from IFR to VFR is a fraught game if the weather is marginal VFR. Having been used to flying on instruments and with nav aids the change to marginal VFR can be disorientating. Much better to have a procedural approach than to be scratching around in the murk half lost.
The problem with flying is rarely do you get what you expect and unless you and the aircraft are equipt to deal with a multitude of scenarios you are asking for trouble. Flying pure VFR. Lowering cloud and vis is obvious. You can always turn back or divert. Flying VMC on top you cannot always see what is going on below and that is the danger.
I myself flying a twin in france left Paris in clear blue skies and sunshine for a coastal destination also in cavok. I couldnt believe my eyes flying VFR when scud cloud appeared which then went solid I was sure it must be localised and continued on top. I changed to IFR when I realised it was not localised and landed in 400 overcast off an ILS at my destination. A front had slipped slightly more south East than predicted.
Pace