I don't know why anyone would wager such large sums based on the outcome of duels, with the unpredictability of lag, dropped packets, 3rd parties nudging/interfering/catapulting you during the duel, etc.
These duel wagers must be unique to EU, because in all my years of cRPG, I've never seen such a challenge offered. When someone goes 22-1, most of the time they just get made fun of for crutching str/armor/hiltslash/crushthrough/whatever.