I have the paid version of TH2 and it's been authorized. So why all of a sudden does it quit working and need an internet connection to verify this? Is this going to happen every time I use it? Do I need to be online all the time for it?

I use it offline much of the time without issue. I am sometimes online and I am aware that it advises periodically that updates are available.

Well mine shut down completely and would not work until I reconnected the internet. Once I connected it instantly Authorized itself and came back to life. I'll keep better track of the details when it happens again.

Just as a matter if interest when you authorized it did you happen to be running as Administrator sometimes things do not stick in this situation.

sounds a bit overmuch

I don't authorize it. The initial authorizing occurs on Overloud's web site which scans my system automatically. I just wait for it to say "Authorized".
 
Since then, when I open a project with TH2 and open the plugin, right across the background is a big sign saying "NOT AUTHORIZED". Once I connect to the internet it switches automatically in less than 0.5 nanoseconds.
 
And YES, it happened again. I guess I need to call them.

Does the same thing happen in Standalone as well as when used as a plugin in Sonar ?

I'll check it out in a few days and let you know.