I agree with those who responded with "check the rules".
I happen to have, in my hot little hands, the catalog/class list for Portland's NW Quilting Expo. It states "Quilt must consist of three layers, with stitching through all three layers and stitching visible on both sides." It also has rules for each category and size of quilt. There is no mention of binding in any of the rules.
Make sure you read the part about hanging sleeves, also.