The Australian Institute of Building Surveyors and Kidsafe have produced a list of the top issues with swimming pool barriers. The top failures are;
Gates that don’t self-latch or self-close.
Climbable objects next to the pool fence
Excess space under the fence, and;
Misuse (e.g. propping the pool gate open).
Whilst I agree with this list, I would have to add trees and shrubs close to pool and boundary fences as another major concern. Kids look at trees like we look at a ladders and stairs, they see them as instant access to higher places.
Kids love to climb, but that enthusiasm should not lead them into trouble. Pools areas are special areas that children should be safely excluded from unless under adult supervision.