I've enjoyed the "unsportsmanlike" Ryder Cup thread because all of us (well, 99%+ of us) are discussing a game with which we have zero familiarity as competitors or caddies. And of course that game is flog: a game played on the men's major professional tours.
Besides putt / hole concessions, what are some unwritten rules governing flog?
Matt Kuchar's dad helped us out in that Masters when he caddied: he apparently broke an entire chapter's worth of URs. Two I recall were: no rooting/cheering and no walking in the through-line.
What else?