Having made both mistakes and poor decisions regarding weather and mission focus I can use my experience to educate pilots to recognise the point when to stop - all part of being a SAR training officer and mentoring junior SAR pilots
Arketip - completely agreed, but DB is trying to show that the proximity of the helicopter was a direct threat to the safety to the car - and, since the cars didn't crash, that can't be true either.
Crab your first point must surely lead you to consider, that at some time before the hover taxiing in fog, a STOP decision could have been made.
Your second point is not in alignment with the 500 feet MSD rules and the guidance and procedures for HEMS and Police helicopters operating near roads. Both these mechanisms recognise the risks to road users by helicopter being too close in the main part, through distraction of the drivers. You are right, no bad events on this occasion but surely you can agree with all other posters with a like mind here, that operating a helicopter in close proximity to road users is at the very best, not a good idea.
Finally Crab, in my case I had a severely injured patient that had suffered considerable compression injuries. As a SAR man you can appreciate the implied urgency to get to hospital. Still no excuse for my actions. I am not sure but I have inferred from you this crew were simply "Training"
Like I have repeatedly said, the wx and the ground are the same for all of us. The fickle finger of fate does not care whether we are SAR, HEMS, Police or just flying for fun. Its all hurts just the same.
DB