I think to solve this issue, the host should provide the table of the participants and their wagered amount, that way all the confusion and doubt will be cleared and this case be close or resolved.
I support this, a contest
should be transparent and
above suspicious because the reputation of the casino is at stake here, you're not giving away hundreds of thousands of dollars for the contest winner, if you cannot hold it for a hundred worth of dollar what more if you have payouts amounting to thousands of dollars, so be transparent and make your contest transparent and unquestionable, it will become a reference on how you manage your casino.