Great article here about the problem with eyewitness identification in criminal cases.
This problem does occur regularly, and generally occurs in a few certain types of cases (burglaries, purse-snatchings, robberies). But a faulty witness ID can mean someone gets needlessly arrested and charged. We had one thus summer – case got dismissed after the witness gave a deposition in which she admitted that she really didn’t even see the culprit.
No one wins when the wrong person is convicted and a dangerous perpetrator escapes justice. Police could avoid this by changing their practices, and courts could do more to block iffy IDs and urge juries to be more skeptical.