In PSE 12 sign in = Activate and when you sign out you deactivate. Just sign in and stay signed in. You don't need to be connected to the internet again, but when you sign out, it's exactly the same as choosing Deactivate in any earlier version. The sign in has nothing to do with revel or other online services. You can set your firewall never to let PSE through, if you want, but you have to stay signed in.
I suppose most of the people who troll this forum are big Adobe fans, so I didn't expect a rational response. I managed to find an ideal solution: uninstall and return PE12.