Uber policy is for you to bring it to them on your dime as part of the uber experience..
Rules in my car where take you shit with you, if I see your shit and still see you I'll honk and try to get your attention maybe even send a text. if I don't get a reply before the next ping it goes in the trunk and is promptly dropped off at the police station or uber office next time I go by one and a drop off receipt is collected.
I won't be bringing shit back to people for free.. It ain't free. It cost me money, and so did the uber ride that lead to the problem most likely.