I have actually pondered an e collar for training off leash at the park. You see, Payton knows the come command, but when he's playing with the other dogs and sees a dog in the distance being walked by their owner, he will bolt after the other dog to say hi! Many people don't like this and I don't blame them, but I thought it might be a way to correct him if he starts running off! Anyone try that for this matter? Payton is 9 months old and we practiced "come" first with a 6 foot lead and then up to 50 feet. He has had it down pat for about two months, but can't seem to get it when off leash!!