I hate it when people leave the cart beside the thing you put them up in, however, an abandoned cart saved my life.
After doing the right thing, and putting my cart up, I was crossing the road to get back to my car. As I was 1/4 of the was across the road, this old woman in a BMW comes about 30mph down the road, and obviously doesn't see me. Luckily, there was a cart about 3 feet behind me, so I pushed it back and rolled out of harm's way. The old woman hit the cart, and stopped after the cart fliped over her car. I ran to my car and sped away.
Good times.