What law did he break? These computers are sitting around unlocked in public with the express intent of letting randos test them out. I'm sure Apple didn't intend for anyone to start installing software, but they could add endpoint security to the machines and they don't. As he said, there's no expectation of privacy in public. There's security cameras running nonstop. And glass windows to the street. Installing spyware in and of itself is not a crime. Lots of businesses do it as a matter of course. If you feel like he made you uncomfortable and has you thinking about something you haven't thought of before, then "art" was achieved.