Upside Down Life Jackets Or Man Diapers

I've been thinking about something I saw while I was at Coon Island on Saturday. While I did not take a picture, I now wish I had. After all the sailboats docked it became really hot and everyone( but me), was jumping in the river and floating down to the end of the dock, getting out and repeating this over and over in an effort to cool off. There is nothing unusual about this activity until I realized that everyone was wearing their life jackets upside down. Meaning their legs had gone through the arm holes, the neck opening was between their legs and their entire trunk was supported by the entire life jacket. They were floating in a totally vertical position, rather than having their life jackets up around their necks. It made perfect sense, you would have much more freedom, support and your arms would be free to assist you. They were referring to them as Man Diapers. I must admit, they looked pretty funny as they waddled up the dock. Another unique behavior witnessed on the River. I wonder if they are doing this in the Delta? It seems like a delta thing.