Are you kidding me? A 5 year old is a baby. There are kid snatchers just looking for children like that. What If he falls in the pond and drowns? What if the wrong coyote walks by? I don’t even have kids and I wouldn’t let a 5 year old out of my sight.
A five year old is not a baby. The world is a lot safer then you assume. Remember the press and other media thrive on fear mongering. That includes fear mongering about children being in danger wherever they go. Ironically the one place that children are most likely to face harm from others is where the gov’t forces them to go for 180 days out of the year. School, especially public schools.
A five year old can certainly be A. taught to swim and B. taught to stay away from ponds. (I am not writing about autistic children. Open water poses a real danger to them. But usually they would be under supervision)
If you live where there are predators then appropriate safety measures would apply. But not every place on this green earth is full of predators waiting to pounce. In fact the odds of that happening are rather high.