I hear people say it all the time and they have no idea why. It’s even rare to find a $50 bill in a casino.
The only place I’ve seen them given out as change was at The Orleans and people were confused.
A lot of people think $50s are unlucky because it was rumored that Bugsy Siegel had only $50s in his pocket when he was murdered. The much more likely reason is that at one point in time they were the most commonly counterfeited bill and gamblers wouldn’t accept them to pay debts for fear of being cheated.These two things created our modern day widespread superstition.