The stats are only stored locally on your machine - see your \misc folder - and yes the db files are emptied when you clear history from the Stats window. The server authentication resulted from the long struggle to stop certain users repeatedly sharing contributor versions. This was the only way that actually worked, in the end. You can search the forum for the full story.
If you want a stats opt-out, please use the Requests forum so it can be properly logged along with the other feature requests.
