Interesting. Let me add a different datapoint from my experience. I have probably just under 1000 hours in various types of aircraft with carburetted engines (C150/152/172/172RG/182, PA28-140/161/180/181, PA38, DA20, AA5A, DR400, Robin 3000, PA18, P2002 and a few more) and in all those years and over all those hours, I have had one single event which might have been a slight onset of carb icing...