Years ago in my country we had the 'pupil worker scheme'. Students as young as 16 (we call it 6th form – I think it is high school in the USA) had to work during the summer and we were paid tiny wages.
My first job in a bank was in a very high security facility where we counted money all day. It was incredibly boring but we had to watch out lest we made a mistake. Some of the other students started to compete with each other to see who could work hardest. I tried to tell them that if they, let's say counted 100,000 notes a day, they would be pushed to increase their output to double the amount. That is what happened.