As we all know, winning can be hard and it can take some time. Some people actually never DO win. That is why the jackpots are usually so high.

The real problem occurs when the casino doesn't want to pay out.
Playing cards isn't a problem (usually). The problem are the slot machines.
IF you hit the jackpot and see the winning amount of approximately 1000.000$ you should make sure to get some witnesses, take some photos and some good legal knowledge comes in handy- if the casino doesn't want to pay out.

One of the more famous stories is when casino Fiesta in Las Vegas didn't want to pay out.
The jackpot should be about a 1000.000$ - tho they say it was a malfunction and want to pay out only about 20.000$.
Right now- the case is being prosecuted at the court.

Good luck.