I remember once being the judge of some small and unimportant contest, and when I sat down to read the entries it became apparent to me that all the best poems were by the same person (whom I did not know, but the style made it clear. Also the type! Remember that your type face can give you away!) Anyway, it somehow felt wrong to give the obviously best poet a clean sweep, so I gave him/her 2 prizes and gave the remainder to middling good poets. I suppose the ethics of this can be debated.
I have often wondered why the same person never shows up twice in the list of Nemerov finalists, but I suspect this is deliberate, and probably wise, where there are so many good entries and everyone is watching the results like a hawk.