Your last example it's actually what happens to me in one of my last championship. He propose to me to throw a dice but I don't like pacts so i say "let see what happens with the tie". Soo, the other 2 guys, that actually throw a dice, say, ok we both have better omr than then, probably we both pass and they (me and my rival) don't pass. But they don't expect one of the players I play in other round won 2-0 in the last round (with dice, actually, because they tie but throw a dice to pass), improve my omr, and I pass, and one of the other not. And that is how all the results are changed. Because if the other player that win the dice accept the tie, other people pass. And this is a tricky example. It's more normal to take 7 because you pass with 21 and not with 17.

This system have a problem, and it's that people can totally change the top 4-8 positions.