I play 777 at an Indian casino in California. I have been fairly lucky from time to time, but there is definitely a pattern to the payouts. Weekends and busy times, it's hard to get anything out of the machine. Week days, especially afternoons I break even or am ahead.
One afternoon, a slot "employee" was hovering around the cluster of machines where I play. I engaged him in conversation and basically he said "I'm hanging around this area because one of these machines (in the cluster) is going to hit and I don't want to be on the other side of the building."
Yup, 10 minutes later a player 5 seats down hit a $5K pay out and the slot employee was ready to pay.
Coincedence? They do not exist.
After attending a Gartner seminar on security, where some industry heavyweights spoke, it is simple. The cost of fraud has not execeded the cost of prevention. It is claimed for $5 a cardholder/card, they could reach virtual stopage of fraud (I don't have an exact definition of that term), but the fraud damage is still cheaper to absorb and/or pass on. It will take an event(s) of unimaginable magnitude for them to implement the additional security factors. I am not holding my breath.