My understanding of the YES program is that if you can get 10 or more kids for a class, then they will hold it. If you are signing up for a class, you are eligible for the discount tickets.
When are you planning on going in May 2011? 14th to the 24th by any chance? What age are your kids/group? I am thinking of starting one for 13-14 year olds for May 14th to 24th sometime. A friend and I are going and I think it would be a great opportunity for our boys.