Just found this statement from the American Society for the Prevention of Cruelty to Animals in support of Dog Parks:

"5.12 Dog Parks

The ASPCA supports the development of community “dog parks” or “dog runs” as a means for urban dogs in particular to exercise off leash and socialize with other dogs. The ASPCA believes that dog parks are beneficial to both dogs and their guardians, who frequently share dog-care information and exert peer pressure on others to become more responsible as well as demonstrate the value of the human/companion animal bond to the public at large. "

Taken from:
ASPCA: ASPCA Policies and Positions: Animals in Entertainment, Sport and Work