[panny]

With regard to plates...

https://www.businessinsider.com/waitress-on-tiktok-shows-dif...

With regard to carts, because they roll around, into cars, and cause damage. Leaving your cart loose in the lot is a great way to damage other people's vehicles. The first ding in my first new car was caused by a loose cart some asshole left in the lot while I was shopping.

[tguedes]

I was going to comment this exact thing about stacking plates. I think most servers/ex-servers also do this regardless of age. It's even easier to do than returning a shopping cart.