Hardly ever see anyone wearing a life jacket ( or PFD) when they come in to the dock here, in fact only one family plane load this year besides myself, (well you have to see my water landings.) Certainly none of the commercial passengers in Beavers ever do and I've never seen commercial passengers in 180's wear them either.
Interesting mention in the article that seems to have gone un-noticed. The plane belonged to the victims father. It is, in the end, the pilot's responsibility to make sure that the plane is both legal and properly loaded but I would not allow another pilot to fly my plane while it was out of annual and if I was around I wouldn't if it was overloaded.
Just for instance, you toddle off down to the FBO and rent your regular plane, did you check the plane was in annual? I never remember doing so. You have a minor incident and the suits arrive. Next thing you know you have a citation for flying a plane out of annual plus a couple for carelessness and negligence just to make sure.
None of this is to deny that we have particular duties to young people. Two of my kids go out every day to guide on a Zip Trek line and another is a lifeguard at a camp working in a sea situation. I wonder every time they go out if those responsible for running these places have taken every precaution and if the maintenance and training are all they could possibly be. (And I do quiz the boys about it all the time!)