I found this link and it is very useful! It spells out what is unauthorized and is should provide reassurance that you always need a contract (& permission) to do any kind of security work on a network. Some states are so tight if your computer happens to hook to an unsecured AP you have broken the law. Read up and notice most of the Laws are aimed at virus and not actual hacking.

http://www.ncsl.org/programs/lis/cip/hacklaw.htm

Slimjim100