I wanted to flag two of the answers to this question as duplicates of the accepted answer, as they were later, and had less information (and thus serve no purpose).
For the flag (can't yet vote to delete) I wrote a custom reason of "Dupe Answer." I was then treated this this box:
This is silly. I am flagging as it is a duplicate answer, not question. Additionally, while for duplicate questions, the moderator that is reviewing the flag may have a hard time finding the "origonal" question, that is not the case with duplicate answers.
As such I think this is a bug (for having duplicate question as opposed to answer) and as a feature request/bug to remove it from the check on answer flags.
Copied from. But indeed, the filter probably shouldn't work for answer. Or they could introduce a duplicate answer flag, although that wouldn't be used much...