I am confusing on your rules
1, you said it's player vs player, if in a game only I bet and win, no other players pay me the money, so casino pays my profit, is it right?
2, if we can set odds, how about people set a very high odds? For example: FC Bayern vs Real Madrid, odds: 10:10.
1 - If you are alone on a single market and you place bets, they will remain unmatched and later cancelled when event starts because no other user will match them. We don't cover user's bets at any time.
When you see an odd with the correspondent volume below, it's other user's unmatched bets. When it's on the green side it means the other user placed a lay bet (bet against), if you want to cover it you will place a back bet (bet on). Following the opposite logic, if the other user (or you) place an unmatched back bet, it will display on the market for other users to cover on the lay side (red).
Please keep in mind that a matched bet has always the correspondent counter bet made on the opposite type (back/lay) by other user.Check this link for more info about matched / unmatched bets2 - Again, this is a betting exchange. If you set higher odds that no one else will be interested to match, it is very unlikely that your bets will ever be matched by other user.
If you still have doubts about my explanation please feel free to reply.