Why do former winners of literary competitions enter them again, year after year? I think those who have already won should be barred from re-entering competitions where they have already walked away with a prize. I also think they should have the humility not to try to win again. It's on the CV, why do you need it twice? It would mean so much more to someone else.
As a personal rule, writers might ban themselves from entering any competitions where they have already been in the top 3. Leave room for others to 'crack' the code of the selecting committee.