Even with fences many have been sued.
Many insurance companies view pools as an attractive nuisance and charge homeowners with any sort of pool a much higher premium expecting the JohnEdwards Ambulance Chasers to sue them.
And so they should. A second attractive nuisance, the bathtub, and a third, the shower are responsible for many deaths. The number 3 cause of death in the US is accidental falls.
Number 1. Car accidents.
Number 2. Heart attacks.
Number 3. Accidental falls.
Lawyers: An unattractive nuisance.
Roughly on the same order: drowndings in 5 gallon buckets and firearm accidents.