There are some things concerning laws that would be good to keep in mind when writing and implementing software requirements. The first one is that laws try to specify what will happen if everything doesn't go according to the rules. It would be good to specify also how software should work in erronous situations.
Another point would be specifying what rules will be followed if there are contradictions in different sources. But most importantly there is always judge or jury who will interpret the rules in real life situation and has authority to do so. Even when strict rules are set there is always ambiguities and exceptions. Someone needs to decide how they are then applied, and it helps enormously if there are high level guide lines and reasoning and rationalizations why things are to be done.