They don't happen very often.
The little star is different in the listing, and it will usually say something like 'starless' or non-subscriber in the title.
You can see an example at:
http://www.redhotpawn.com/tournament/index.php?&view=&page=4
Look at the Xmas starless duel.
But like I said, they don't happen very often. If you subscribe, there are lots and lots and lots of them....
--tmetzler