As a network security engineer, I can comment that in the state of California, unauthorized use of a wireless access point is considered theft of service and is a felony.

LOL typical “network security” person. No, it’s not illegal, and lots of people do it. If you don’t secure it, then it’s open and your computer without modification will connect to it and use it. Nowhere near illegal, tht’s just something that old people and full of themselves say. Why not help people secure their networks if they care instead of making stuff up.