In my unqualified opinion, I would think having an iCloud account tied to the device that the person in possession of said device doesn't own shows "clear and compelling testimony or documentation to the contrary [of them being the rightful/current owner]". Although, I can see how others might argue it proves nothing; in the end, neither side is probably 100% correct in all of the scenarios, and it's all up to interpretation.
All I know for sure is I can say I'm glad I'm not a lawyer!
All I know for sure is I can say I'm glad I'm not a lawyer!