Offline mode allows access to full version of the game, even if not premium

As recorded at http://gaming.stackexchange.com/questions/95632/offline-demo-save-data-to-full-version?rq=1:

1. Download the launcher
2. Log in using a non-premium account
3. Exit the game
4. Disconnect from the internet
5. Reopen the game

According to the link posted above, this can be used to access a premium single-player copy of the game for free. I have not tested this, and this was posted back during 1.4.5, so it might be fixed now.