DB .... You have got to be joking . I only get probably 10 days a year as good as that .
We all know that low cloud base and poor viz can be dangerous but equally it can be perfectly safe ( with ref to CFIT ) . 4-500 ft with 2-3 k viz is no problem if you just slow right down and keep a minimum forward visual distance . If that reduces to 1 k then stop ! More rules will do nothing to help . How many people get taught how to fly safely in deteriorating weather ? . When is time to say no more ?
Some of us were lucky and have flown with mentors but most are just let loose with their licence to learn their by their mistakes . Inadvertent IMC means you were going too fast . Even when faced with an oncoming fog bank you still have time to turn or land if you are going slow enough . It is no different to driving in fog and being able to stop within the distance you can see . You would never attemp a VFR flight at that height in the hills , so he was either intentionally IFR or went inadvertently IFR and was climbing to MSA . I can't see any alternative .