Was collecting carts and moving down a slope. Hadn't secured it yet because I still had more to grab. Carts came undone from the machine and the one at the very back somehow detached and rolled down to hit a car. No damage, but still felt bad. Had a similar incident about a year ago.
When the grade is downhill, you'd best have the rope attached OR be controlling the front cart COMPLETELY OR change your route so you will be going UPHILL.
I had control over the front cart, but the back cart detached and you have to go downhill first in our parking lot. No other way around it. Rope was the only option, but I've never had a cart detach like that. Unfortunately these ones can't stick together whatsoever.
It's just a rope that stretches over the length of the carts and hooks onto the front one to keep them from detaching when you're operating the cart machine.