Polo Rules: Shot blocked by a footdown

Don't play yet, but surely if it didn't go in, you can't know for %100 percent certain it would have, so it has to be Penalty shot on goal.

I'd like to say accidental - Play the advantage, and player taps out
Do it on purpose - Goal
BUT, how do you police that? I wouldn't have thought you could? Can a game (some kind of 'fun time' activity) really rely on decency, honesty and good sportsmanship?

no polo no talk