All Intensive Purposes

Alex Tabarrok explains why small children with an aptitude for economics self-select out of the population:

The boys were tossed out of the ball pit for rough-housing. The wife began to sternly lecture them "Why are you so wild? Don't you know you could get hurt?!" The 5-year old retorted, "Mom! No risk, no fun."

Naturally I burst out laughing. Need I explain why this was not wise? I should have kept quiet, but I learned another tradeoff; no fun, no risk.