If you were on a budget and in desperate need of reckless endangerment, 1960s suburbia offered easy-to-assemble hazards that any doofus could construct "in a few hours." For example, this guide teaches you how to combine toddlers, mesh netting, and water into a single Sudden Infant Death apparatus, for convenience.
Maybe you're thinking the family pictured is in a shallow lake or pond. You're wrong. The whole point of the water coffin was so that Mom and Dad could have fun without having to worry about keeping their babies' stupid faces above water. Deep water was the name of the game, and children were the albatrosses holding you down.
Or if a riptide carries them away, whatever.
The best part of the cage was that it could fall apart with a simple pull of a pin or a hard wave. Guess what Mom and Dad were doing while Junior earned his life insurance deductible? Having FUN on their homemade water-ski ramp, that's what!