I never wanted a harness so desperately in my life until a couple years ago my in-laws brought our niece(then 8) and nephew(then 6) up to visit and we went to Dolloywood. The ENTIRE day all you could hear from my DMIL was "stop, come back here, ok now lets go" over and over and over and over. My nephew was rarely more than 8 foot in front us and we could always see him, but my DMIL was so paranoid that he was going to be kidnapped that I searched every store at the park, praying that I could find a lease if only to get her to hush.
Now, that I've typed this I need to clarify my meaning. I know that children can be kidnapped and they should not be allowed to roam away. The problem that day was the way that my DMIL was handling it i.e. making him walk back to us only to have the whole family walk straight to where he was when she yelled stop. Poor kid retraced his steps too many times to count and I don't think my DMIL relaxed the entire day worrying about him and his sister.
And for anyone who thinks putting a child on a leash is treating them like a pet I would consider that a compliment simply b/c I put my dogs on a leash b/c they only listen when they want to and I don't want them to go running off into the street and getting hit by a car. My dogs are my children and their safety is of number 1 importance. Plus, I'd rather have the leash than having to yell at my child every five minutes to "stop, come back, ok now lets go"

It wouldn't take too long before that parent lost that magic feeling.