child labor
My mom told me a story about the time when my dad wanted to make my brother mow the lawn on a riding mower when he was 8 years old. Unfortunately, forseeing my father's affinity towards child labor, the makers of the mower incorporated a feature that would only allow the mower to be turned on if a certain amount of weight was on the seat. And since my brother was not heavy enough the mower wouldn't start. My dad quickly resolved the inconvenience by placing a brick on the seat to go along for the ride.