They didn't have "unlimited decision making" authority. Their parents had limited them to the water way and rivers. They weren't supposed to go outside. When you're that age though, you think you're immortal. I know I was.
I'm sure that is the truth too....that inlet took the life of an experienced charter boat captain just last summer.....a pro who goes thru it a few hundred times a year.....in a 51 foot sport fish boat. No place for a couple of young teens in a small craft.
I used to do exactly what these kids did when I was 16. Gulfstream, no life jackets, no radio, no float plan but plenty of beer and bait.
I have no doubt that God was watching over me during that foolishness.