How does that "ban them from working at at[sic] a competitor at the same time"? So, you fire them. They'll still have the other job and can get another.
Im not sure what part you are confused by. Is it the word ban?
My employer can also ban me from stealing money or tools. If they discover it, they can legally fire me.
You stated that non-competes are illegal. This is incorrect in the context of moonlighting with competitors or concurrent employment (with anyone during working hours). Those types of non-competes are completely legal.
I expect we will see a rise in the number of contracts that explicitly state no other employment during business hours.
