You do not have to join. Its open to the public, but you will not regret joining BHA. Its well worth it. It's $15 a year to join. You'll meet and make some great new friends.
Ya'll enjoy it. My Mom is going to make her bow tournament debut at this one. It ought to be some good quality entertainment. Hope there aren't any small children shooting in the group with her. Sure hate I'm going to be in Iowa scouting and hangin' stands. :p