I think there are variations to the game. I think the big way they win is that the "hopper" is full of those "Doubler" balls - it doubles the jackpot, but doubles your bet as well. Eventually your bet gets doubled until you can't cover it, so you lose the jackpot.

I had never seen this game until I went to the Princess Casino in Antigua. I watched a couple get to 99 pts., but on their next draw, their bet had doubled. They had to put up $4K in order to get another ball and possibly win something like $80K. They couldn't cover the bet because they had maxed out their credit card (which the dealer had held along with their driver's license), so they "lost" the jackpot and $2K.