Guests grabbing from fulfillment cart

When guests approach your cart and start hovering/handling over items. How do you handle this? What do you say?

I was near my cart looking for a clothing item with my RFID. All of a sudden, I hear…. “Do they just leave random carts with items for customers?” From two teen girls that started grabbing stuff from my cart. I immediately went over to my cart and said “I’m sorry these items have already been purchased, and are for a guest - they’re for an order” thankfully they understood.

Overall, I’m just wondering if anyone had similar stories.