Would you believe a slot card from the MINT in LV which closed in the 80's way before any machine accepted "slot Club" cards? Coupla' years ago about 4 of the gray Mint Slot club cards were found with the magnetic strip and all but we could never find the history of its use. I sold this and traded the first two to "Mint" Casino specialists...not slot card collectors and still have one left with a price tag of $35....
Another historical interest is a seminar held back in the early 90's late 80's at the Gaming Expo of those days......some wise guys from the credit card interests tried to create and exploit a plan to have credit cards (Visa/MC) used in slot machines to play in slots by creating slot clubs (comps etc) to aclimatize players to use their club cards to be later (5-8 years) into slot/credit cards so immediate play on any machine could go to the max of the cards credit line. Arguements against it were from those that felt slot players would never join a "club"....Looks like wer'e there now and expect to see you slot card being upgraded to a card that enables one to play up to their credit limits next.....and then cards will not be left in machines etc.....
Think of the pitfalls to the gambler. Play your credit limit and even when you win ...most play a lot back, but even if you cashed out at the cage...your credit card has not been payed of til your monthly bill arrives and most of the cash you get from the tray or cage will be put back before you leave the gaming tables/slots etc. One way money and lotsa 18%-24% bills at home when the card/ gslot machine play is billed to you later.....Whew?!!!Mel