Asked by user in Rhode Island.
I hit a car slightly backing up and the owner of the vehicle didn't notice any damage. They just pulled away and we didn't talk.
Under Rhode Island Code §31-26-2, a driver of a vehicle "knowingly involved in an accident resulting in damage to a vehicle" is required to stop at the scene and exchange their insurance information with the other driver.
The law does not require a driver to do anything if they were involved in an accident that didnt result in any damage. In other words, you haven't done anything wrong under the law. However, if the other driver later discovers damage to their vehicle caused by the accident, the driver could attempt to file an insurance claim or a lawsuit against you.
It's a good idea to take time-stamped photographs of your vehicle so the other driver cant later claim that you caused more damage than you actually did.