No, that would be "triple your jackpot" (variations of which can show up on occasion). Cashback in this instance, as in most instances, refers not to payouts from the machines themselves, but to a rebate percentage on your action. Cashback works much like casino complimentaries: The more money you put through the gambling machines (slots and video poker, video keno, video blackjack, etc.), the more the casino returns to you in perks, benefits, freebies, which are all known as comps -- and actual cash, known as cashback.
You must be in the player-tracking system (also known as being a member of the slot club) and have your player card inserted in the machine; the card-machine combo electronically tracks your action. Each casino awards comps and/or cashback (some only award comps) according to its own formula. But a typical example might be the fictional Hats and Horns Casino, which gives back .5% of your action in comps and .1% of your action in cashback.
In other words, say you play $10,000 through a video poker machine during a three-day visit to Hats and Horns. (Note that this doesn’t mean you have a $10,000 bankroll. You might have a $500 bankroll, which you manage to stretch into 20 hours of play on the machine, with the slot club tracking every bet you make.) According to the formula, you’d be entitled to half of 1% in comps, or $50 worth, and a tenth of 1% in cashback, or $10.
Now, triple cashback means that for the same $10,000 in action, you get three times the normal amount. In this case, Hats and Horns (or Ellis Island) will give you back $30 in cash. Casinos often run "multiple-point" promotions on holidays, whereby if you come in and play on that particular day, you get more cashback and comps for your play.
