Here's my take:
When I only had my first son I did have the attitude of, "I would never put a LEASH on my child -- how awful!" My son also happened to be a very quiet, non-impulsive kid that would never have dreamed of running off. And of course, there were two adults to handle one child, and never a fear that he wouldn't have at least one adult's undivided attention.
It is easy for people to believe that their individual experiences with their children can be extrapolated to apply to every other child in existence. ESPECIALLY when they have only one of their own, and really no room for comparison even within their own family unit.
My second son was/is the complete opposite of my first. Where #1 was more quiet and reserved at 2, #2 is more gregarious, more outgoing -- and far more impulsive.
The biggest lesson I learned is that all children are NOT THE SAME!
I also learned that saying there are things you would "never" do is really just a bit sanctimonious, and really not all that practical in real world applications.
Now in my family there is only one adult per child. And one of those children is likely to run off to see something exciting with no backwards glance. And on our trip to Disney last summer (just before the little wild child turned 2), what worked for my family was this little baby right here:
http://www.target.com/Eddie-Bauer-H...frombrowse=0&index=target&rh=k:harness&page=1
Now, the only thing I would "never" do is let aesthetics or a judgmental attitude prevent me from making a safe choice for my kids!