Currently, user shopping carts are not visible to other users. It also isn't possible to see everyone's shopping cart from one username. If an animal(s) is in a user's shopping cart, only that user or admin can remove the animal from their cart.
If you happen to see that an animal is currently in another user's shopping cart - below are options to remove that animal(s) from their cart:
1) The user removes the animal from their cart - If the user is present and available to login to their account, they can remove the animal from their shopping cart.
2) An admin removes the animal from the user's cart - If the user isn't available, a manager with the "Configure my shelter & its Users" permission will have to manually reset the user's password to gain access to that user's account. Once they are in, they can remove the animal from that user's cart.