From "Law and Order" to "CSI," not to mention real life, investigators have used fingerprints as the gold standard for linking criminals to a crime. But if a perpetrator leaves prints from different fingers in two different crime scenes, these scenes are very difficult to link, and the trace can go cold.
I always assumed it was a bit like SHA hashing. Yes, collisions are theoretically possible. But they’re so unlikely that it can be used as a unique identifier for most purposes.