I dont know if the park has any rules but the dog parks around here require all the male dogs to be neutered. I dont have any advice but that is one reason I am not a fan of them.
Lucky's mom....Thanks so much for your experience. I like the way that you described Lucky as taking advantage of the opportunity of being dominant. I really think that is what Paxton is doing and it is nice to hear that Lucky is not like that now.I think it could be more of a puppy type stage then a nueter issue. I say that because Lucky was very "unstable" in his behavior until he fully matured. He did take advantage of situations when he had the opportunity to be "dominent." He wasn't "trust worthy" then...but he most definately is now.