That is something I would not do , someone could try to steal my pocketbook or wallet.
No more so than anywhere else you would have it while in line. You are right there by it with someone else just adding their things after you. Or you are beside it with your order following it on the belt.
I think because im a scary looking person
You go to pull in a space ( especially when you find an AWESOME ONE! ) and oops, there it is... someone left their freaking cart right there dead center in the freaking parking space!