Severability Clauses
If you are sailing close to the wind, add a "severability clause" to your non-disclosure agreement. A "severability clause" is a useful bit of boilerplate. You will find it in many different types of legal contracts. What it says is this. If any clause is determined to be invalid, the entire contract should not fail simply because of that one invalid clause. Instead, the invalid clause is "severed" from the contract, hence the term, "severability clause". I have seen some rather creative severability clauses. For example, instead of severing the clause altogether, the parties agree to "reinterpret" the invalid clause to the extent required to render it valid. Lawyers never give up, do they!

http://www.technz.co.nz/business/nondisclosure/nondisc10.htm