However, California courts will enforce contractual provisions to protect trade secrets and client lists, and if this is an interstate issue (e.g., prior employment and noncompete were signed in New York, with the work performed in that state) it may be possible for the former employer to take legal action in that other state then seek enforcement of any judgment or injunction in California.

It is very sensible to take the suggestion of having the actual contract(s) reviewed by a lawyer.