Personally, I am in favor of toddler harnesses and leashes. For those of you not familiar with them, they consist of a vest-like harness that the child wears. Attached to the back of the harness is, well, a leash, or a lead. Sometimes the leash will have an adjustable, velcroed end so that it can later be used on its own with the child, with the adjustable end going around the child’s wrist. That is something I would not use, as I’d rather my child be comfortable in a harness, where the pressure of him pulling or tugging would be evenly distributed around his body, whereas with a leash the pressure would be on his wrist and arm.
We used a toddler harness with our daughter, and we use it now with our son. They’re a great way to give your child a chance to explore his surroundings in a safe manner. Hand holding isn’t always feasible, especially when you have a child tugging and twisting because they want to walk a little ways ahead of you or beside you, rather than right next to you. Also, it frees up a hand for you, since you can easily hold onto a leash by slipping the looped end around your wrist.
When we go for walks together, my son wears a harness. He tends to just make a beeline for anything and runs all over the place, and with a harness I can keep him within a safe, secure distance, while still being able to pay attention to my daughter.
My answer for why I’m in favor of toddler harnesses can be summed up in one line: Better a leashed kid than a missing, injured or dead one.
My name is Jenn, and I'm 27 years old. I'm happily married to my best friend and soulmate, Daniel. Together we have a seven year old daughter named 
Name: Alyssa
Name: Ryan
Yes, I absolutely would. I don’t see why not!?
My mom used to use a harness with my younger sister. Worked wonders. We never lost her. Darn.
I totally am for them as well. And I really need one for my son. The problem is…he has a talent for getting out of stuff like that. So I don’t think it would work.
I don’t even have any kids and I think this is brilliant. It really is frustrating seeing toddlers run amock with the parents no where in site and they aren’t even looking for them either. My mother refused to take us (I’m a twin) out until we were like around 5 and behaved to know not to stray anywhere and to be as behaved as we can or she was going to cut our butts and she had no problem doing it in public either.