I believe that a mistaken identity is already a reason that an RDM is not considered as such regarding perpetrator intent. Victim gets comped, perp is told to be careful and isn’t even noted because it’s just a mistake. Like in this scenario; if he identifies the package holder and an identical person gets shot once he’s out of range and there’s a mix up due to line of sight breaking or some such reason, it’s not exactly an RDM. Just a mistaken identity.