I wouldn't object to banning them either. They are nothing but trouble waiting to happen.
Wow... really?! REALLY?
I don't believe that everyone should be punished because of a few (ok, maybe more than a few) morons. Do I think dog parks should require a membership, which includes all of their information, proof of vaccinations, that the dog is over 6 months old, and a temperament screening? Yes. I also feel that it's ignorant and rude for dog park designers not to include at
least one seperate "run" for people to exercise their dogs who are shy/reactive/insecure/unsocialized. You simply cannot expect dozens of dogs who don't know each other to hit it off instantly, especially with the lack of dog knowledge in so many owners.
One of our local dog parks has a solitary section that has plenty of space, is usually empty, and requires that anyone who wants to enter asks permission if some one is in there. I would love to see this, and more of them, in other dog parks. It isn't easy to find dog-friendly spots in most areas, especially in the city. Let alone find places to bring a dog who does not do well with a pack of strange dogs running up to them.
As far as prey drive in Greyhounds, I do sympathize. I know a few people with Greys who can get "turned on" when there are small dogs running around. For sighthounds, I think it's a good idea to put a soft or basket muzzle on them to prevent incidents. However, that does not make them aggressive at ALL. There is a lady at one of the local dog parks who brings her Greys in the large dog side, and they will occasionally eye Fozzie... once, the owner told one of them "that's not a rabbit!". Whaaa? Does that mean I should not bring Fozzie in the large dog side, even though he's near 50 lbs, because he's height challenged? If her dogs will treat a 50 lb dog as prey, they definitely should be wearing a muzzle of some sort or dragging a long line.