Wow, there's a lot of people on here giving bad advice.
Restrictive covenants are enforceable providing they are not wider than necessary, are reasonable in time and area, the employee is an appropriate target and they're protecting legitimate business interests. However, an employee must be allowed to earn a living.
You'll probably only find they'll enforce the clause if you're a higher up and may take clients with you. I'd only start getting worried if a client switches from them to the company you work for.
Restrictive covenants are enforceable providing they are not wider than necessary, are reasonable in time and area, the employee is an appropriate target and they're protecting legitimate business interests. However, an employee must be allowed to earn a living.
You'll probably only find they'll enforce the clause if you're a higher up and may take clients with you. I'd only start getting worried if a client switches from them to the company you work for.