It's standard policy to allow pets into pet stores. Pets are after all the consumer of the product. As a pet owner I enjoy bringing my dog into pet stores, where she gets pets and treats and such. It is rare for a pet to defecate in a pet store - as a pet owner I would not bring a dog that wasn't housebroken into a store. And if my dog did have an accident, I would feel responsible to clean up the mess and get staff to provide me with what I needed immediately. This is not to stay that the store isn't liable - I have no idea whether or not it is.