What I'm hearing so far is that it's hard to hang liability on the pond owner. That suits me just fine.

There's an old saw that goes "Ignorance of the law is no excuse". IOW, you are responsible for breaking the law even though you weren't aware something was illegal. I have no argument with that.

Now, why not say "Ignorance of danger is no excuse"? In other words, if someone jumps in my pond and drowns, it's their responsibility because they should know that water will drown you. By building a fence and posting signs, it assigns the responsibility to me to inform them of the danger.

Looks like we're stuck with a double standard, and I will always be worried.