Simply by having an escrow equal to the buyin a secure contract could always be held between staker and stakee. If a player wants to play a $10 game but has nothing to escrow (or for example only $1, perhaps then that player should and might advertise to play a $1 game with a $1 escrow and a $.1 fee to the escrow bankroll. After 10 games or stakes there is now a $2 escrow and this player can move up and advertise $2 contracts.
Players have incentive then to keep accounts credible or lose their escrow/bankroll, and one’s ability to get staked for that level of games.
There can be different ways for players to link different sties and account to the Staking Account, basically via pub/private key and api’s.
The staking can all be done with an internal currency with a finite supply. Once the contract is started money can be sent via site policies.
Multiple lines of arbitration could be used. Data mining, and data mining companies. Tracking sites. Could be anonymous or not. Could be smart contracts/oracles or not.
Players are free to engage with untrustworthy accounts (probably of “site”).
There can be a main forum, but also other forums could participate.
Because there would arise a market for profitability, effective rake would be highlighted on each site. The demand and liquidity would incite competition within the industry.