Yes, haha, I was aware that the motivation for my suggestion may have been flawed, this is the kind of thing my brain doesn't cope well with.. You say it's possible that half the games would be downgraded but I was wondering whether this would be a certainty just from the nature of a median value.
But it does make sense to have some kind of downgrade system so that a game with one five star vote doesn't win. For me, the solution lies not in the results system but in the voting system. After playing one game that must have been entered into another jam as well, I must have clicked on the wrong entry page link as it was telling me I couldn't vote for the game until I'd voted for some others with few votes. I feel like forced voting like that could lead to just voting a low score without even playing just to get back to rating other games faster.
I think I saw some mention somewhere of some jams where the submissions only have one ordering filter, that is the games that have voted the most are displayed at the top. But once again that could lead to dummy voting.
I can't really think of a good solution that doesn't rely on people doing the right thing. I think the biggest contributor in this jam to the ratings gap was the rate for rate posts. I don't know if all jams are 'plagued' by such posts but I can't see any way of having a fair jam while they exist.