Using broken slot machine is against the law?

Confusing title I know, but it’s a weird case. According to Yahoo! News, a machine at Caesars Indiana casino was crediting players with $10 for every $1 inserted because it wasn’t properly designed for U.S. currency. When a player finally informed Caesars, it was out almost $500,000 (small change for a casino). Now,  prosecutors are considering criminal charges against the players who used the machine while it was broken.

First of all, serves them right for converting voting machines into slot machines (sorry, I had to). But seriously, casinos are practically licenses to print money. Everything is rigged so that the casino always comes out on top, but if the player start winning, it’s time for the lawsuit? And besides, as Kathryn Ford in the article points out, if the machine had jammed, the casino wouldn’t have refunded the player’s money. They can’t have this both ways.