> The best thing would be to ban these sites.

I think we could legislate some easy-to-understand, easy-to-enforce rules. Like, "you can't have more than N bets open at a time." (1?) Or, "you can't have more than $1,000 worth of bets open at a time."

True, addicts could skirt these rules by having different bets on different sites. But at least it would add a little friction, and it would be easy to monitor compliance.