do you have a written contract , one for each employee ?
did he edit the handbook himself or hire an atty to do it?
if not, it'd be unenforceable
also, the employer seems to be confusing non-compete clause (which is a geographical restriction concept) with intellectual property theft (the client list is owned by the company).
enforce-ability of a geographical non-compete clause is based on a "reasonableness" standard for a given trade.
for example, for a veterinary associate, a 2-mile radius for 2 years is enforceable. any more or longer is unreasonable.
for an owner of a veterinary clinic, a 30-mile radius and 5 years is likely enforceable
