Any unpublished game with a sneak preview can be played by anyone. It is ok (even useful sometimes).
The description of the sneak preview option says: "When this box is checked, this storygame will be visible (but not clickable) on your profile page. If unchecked, the only author(s) may view it and it will not be shown in your profile."
It doesn't clearly state whether it allows the game to be played by anyone or not, but an unsuspecting new author naturally concludes that it doesn't. Many authors don't want their unfinished work to be seen, but enable this option to let others know on what they are working. Later it comes as an unpleasant surprise that others play it.
Examples of 2 such cases are in this thread: http://chooseyourstory.com/forums/writing-workshop/message/15913
This also looks like a grammar error: "the only author(s)" (but I may be wrong).
The proposed new option description: "When this box is checked, this storygame will be visible (but not clickable) on your profile page and any user will be able to play it by entering a URL with the game title. If unchecked, this game will not be shown in your profile and only the author(s) will be able to view it."
Implementation time: < 1 minute.
It will benefit new authors who will not get an unpleasant surprise because of that misleading description.