I noticed that user Parzival recently posted answers to several questiosn (here, here, here, and here). Each of their answers was the exact copy of a highly upvoted answer. The last link even had a user point out that Parzival might be copying previous answers.
(Note: I'm just using Parzival as a recent example; I have seen other users do similar things.)
Should there be a flag for answers that are duplicates of other answers that other users have posted previously?