Normally i Casino has no right to denied any gambler right in claiming his winnings because of geographical location and this shouldn't be a barrier for a gambler to claim his win, they can refer the gambler for security reasons and make it official, as to the best of my knowledge most casinos don't award big winnings in their local offices, they will always make a need for the provisioned to be transferred.
Except for the scamming casinos will act such a way without presenting winners their winnings, reporting to the local authorities isn't effective enough to tackle this, but one can also take a legal action against them if such could happens, let also try to investigate on the kind of particular casino we make use of in playing our gamble in other to avoid future disappointments of such manners from any.