I went to wikipedia, hoping to read a cool article describing three pairs of people with
identical fingerprints. Boy was I disappointed.
This wikipedia article (http://en.wikipedia.org/wiki/Fingerprint) lists several cases where
fingerprint evidence was misleading, but none of them were likely due to two people actually
having the same fingerprint. One was a blatant clerical error, and one was simply shoddy
police work. In a third case, DNA evidence freed the suspect, and later investigations
concluded the police had misidentified the fingerprint.
The final case had a police officer's fingerprints found at a crime scene where she claimed
not to have been. Early fingerprint experts were of mixed opinions, but later examiners were
overwhelmingly convinced that the fingerprint was not hers. The image may have been ambiguous
and/or there may have been manipulation of the evidence.
So while I'm not a fan of biometrics, and I don't have absolute faith in fingerprints, this
particular article doesn't provide proof that there have been collisions.