If the employee has signed a restraint clause, the restraint stands unless the employee can show that it against public police, unfair, unreasonable. The court will determine and may "amend" the terms of the restraint, uphold it or strike it down.

If an employee leaves, but has no restraint clause, then the company has some protection in terms of common law, fair business practice and such. Examples are where the employee is approaching clients directly. There is also trade secrets which give the business protection.

The court has to balance the ex employee's right to economic freedom against the rights of the business owner.