Obviously this was a terrible accident but one of the advantages a helicopter has over a fixed wing aircraft is that during take off to the hover, the pilot can check his power available & c of g which the fixed wing pilot can't. Therefore that pilot must do his calculations before attempting take off. I'm sure there isn't a helicopter pilot anywhere that hasn't taken off over weight or on c of g limits without having a good idea that was the case.
During 45 years of helicopter operations I have often had to off load freight or people as I was clearly over weight. This can happen when you are doing running turn rounds & someone else is doing the manifest. The worst case I had was when I was given a manifest for a 212 & was 2000 pounds over weight! The controller had put the 12 passengers & freight onto one manifest, not two!