Is there a means to allow users to only reply to a thread one time? We from time to time have giveaways on our forum. To enter we simply let people reply to a thread to be entered. Then draw a number at random to correspond to the number of posts in the thread. Undoubtedly we end up with people trying to enter multiple times. (Some intentional and some mistakely) Is there any means to restrict users to only one reply in specific threads or forums with the stock xF software? Or perhaps is there an add-on that could do it?