It’s not even necessary to challenge it. You quit, go work for a competitor, they send you an angry lawyers letter threatening you, you ignore it and the company backs down. Unless you are legitimately stealing their customers, it’s not even worth the cost of filing a lawsuit for an employer to go after an employee for violating a non-compete, so they just stop at the angry lawyers letter.
It’s not even necessary to challenge it. You quit, go work for a competitor, they send you an angry lawyers letter threatening you, you ignore it and the company backs down. Unless you are legitimately stealing their customers, it’s not even worth the cost of filing a lawsuit for an employer to go after an employee for violating a non-compete, so they just stop at the angry lawyers letter.