Those tricks are very old but that does not mean they are not effective, another trick that I have seen casinos employ is that if you are betting large sums of money they will offer you all the drinks and food you may want, with the idea to keep you in the casino and in the case of the drinks to lower your ability to think in a rational way, that way you are more likely to lose money in whatever game you are playing, this is why when you go to a casino you should never carry with you more money than what you are willing to lose otherwise you could wake up the next day lamenting all the money you lost.
With such action the gambler who are betting huge amounts of money will be more aggressive, alcohol affects how he treats the game. It's really common inside the casino house they've wanted to make sure that gamblers will feel the comfort and think that they are giving them special treatment without noticing the real intension.
They've wanted to make sure that the person will continue and stay inside the table and keep betting.