If someone is good enough to make a winning entry multiple times in a row, I kinda feel like they deserve the reward.  I'm not a fan of saying something like "you've won once, now you can't win again, everyone's gotta be a winner".  It will definitely be a consideration, but I'm not going to flat-out deny it.  I suppose a good deal of it rests on the shoulders of the participant; if someone wins, they can decide whether they want to try to rack up more wins or give everyone else a better shot.