On the possibility of writing laws to be completely unambiguous:

Except for trivial cases, no way! I think Godel's proof that Bertrand Russell's Principia Mathematica was a fool's errand applies here as well. There will always be cases at the edges that cannot be decided simply according to the letter of the law. Judicial interpretation and decision will be required -- judgement. Case law can refine but never perfect statute law.

This is true of any sufficiently non-trivial system of logic (for a broad application of the term).

yours,
Michael