My youngest son would wiggle out of his stroller and run. If we were in a store he would run right out the door. I had to finally give up the stroller-it became a hindrance.
I tried the leash, but it only lasted about a half hour. He hated being confined and would simply lie down wherever he was. He totally defeated the leash and I gave that up also.
This was before the madatory car seats for infants or toddlers. The only harness he ever tolerated was a harness that was attached to a seatbelt attached to the car floor. It allowed him to stand or sit in the back seat. It allowed me to drive without worrying about him climbing out the window. What a challenge he was!
One of the workers at the grocery store came up to my twin daughters (almost 12), and reminded them how wild they were when they were little.
He told them how he remembered them running opposite directions around the grocery store.
My girls were so embarrassed, but they were also laughing.
Now, I miss them being wild little girls.