|Answer: If the cart is "stolen," it may not be used. However, it is questionable if you should suspect this happened when it is possible that one store purchased old carts from a second. Additionally, it may be that both stores are owned by the same corporation and share assets. Furthermore, it is possible that there is an understanding, verbal or tacit, among the store owners to share carts.
The bottom line is, I just do not know enough about the circumstances to give a definitive answer regarding an admittedly suspicious situation.