Mac Address device.

You can fake it IP and other, but cannot fake it the device. But it's rare things casino get some access device of their user or customer or having some script to view any user mac adress. But, I'm pretty sure... checking mac address is the solution.

No body got a lot device, maybe 2-4 at least but still every way we are using there always have some cheater and abuser. Just matter of time.