I have a question for those who allow thier dogs to run/walk unleashed in public places. No matter how well trained a dog may be, it's still an animal with unpredictable tendencies. To keep your pet leashed allows for more control of the dog for both the dog's own sake as well as those around you.  
 
What gets me the most is when people will let thier dogs run/walk free and they keep the leash in thier hand, not attached to the dog. Do you really think that when that dog darts off you'll be able to get the leash on it?  
 
If you are in an area where you know that the dog is safe, such as a dog run, when it is known that the dogs are not leashed, then that's fine, since it's a situation everyone knows about.  
 
In our town, there are leash laws ( probably why people hold on to leashed that are not attached to the dog ) but they are not enforced. My father and one of my dogs were attacked by a dog that was running behind a woman on a bike. Our dog was tied up in our yard. The other dog ran over into our property.... 
 
The woman seemed to think it was our fault that her dog wouldn't listen to her and come back to her. She also became upset when my father kicked at her dog to get it away from him and our own dog, since it was biting... 
 
This may be a bad example, but so many people have this whole "not MY dog" attitude. Animals are unpredictable, we can't understand them or thier communications totally. Isn't it better to be safe?