"None were wearing life preservers".
I started wearing mine after two things happened.
First is, with the wife in the boat to help if I needed it, I jumped in to see how easy it would be to climb the motor to get in the boat. I was very confident it would be no problem. Yeah, not so much. I was beat up, tired, had some fresh scrapes, and that was in not horrible conditions AND I had already taken my jacket off. If I was by myself I may not have gotten back in. Try it! It's fun!
The second was helping try to locate a couple of bodies of friends that rolled their boat over. No Life vests on either. They floated up a few weeks later.
Put the vest on.