No one is forced to sign a non-compete. If someone has questions about whether signing one is in their best interests or not , that's why we have lawyers in our society. Run it past the shyster, and he'll give you the plusses and minuses.
I don't see where the government should be banning this kind of thing.
If I owned a sandwich shop, I sure the hell wouldn't want someone I was mentoring to become a first class sandwich artisan to pick up and leave for the competition immediately after I trained him