Good Post.

Here's a potential problem.

The kids who work at the register are actually sales people as their friends come inside the store to see them. Without the high school kids working at the counter, the other kids may go elsewhere.

I also eat at 7 Eleven that has machines instead of kids at the counter. You set your order and someone in the back cooks an serves. What's missling? All the high school kids who are at McDonalds!