It's very difficult to imagine how a SEATBELTED passenger can be fatally injured, but one wonders if those chartering private jets think they are somehow immune to Newton's Laws of dynamics.
I certainly recall an article a while ago of the large press party accompanying the USA President, not in AF1 but in a following chartered airliner, who said that quite a number of the journalists liked to smirkingly stand up during takeoff, because "it's our charter, so we don't have to do seatbelt rules and things. Yaa Boo !".