Interesting. I wasn't aware of that, but will note that it's only for 90 days (which would cover most summer jobs, though) and the employer must pay more if the state/local minimum wage doesn't have the same under 20 exemption.

And yes, there is some parallel to internships which are generally paid at a rather low rate (often lower than the lowest equivalent employee; a CS intern is going to get paid less than a 1st year out of college new hire developer). But they're still being paid, and it's still the minimum wage (even though it's a lower minimum wage than for those over 20).