Books have been set forth on this item, and the conflict and disharmony about where the "hot" slot machines are placed in a casino are still bubbling – 60 years after slot games were 1st placed in gambling houses.
The traditional rule is that the superior one armed bandits were positioned just inside the main entry of the casino; so that individuals going by would be able to see jackpot winners … be challenged to come unto the gambling floor and play. Our leaning is that this is not so anymore.
The great majority of the large casinos today are humongous complexes … you can no longer see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slots close-by any doors.
Another classic rule is that loose slot games are positioned on the major aisles inside the casinos, again so that more persons could see winning jackpots and be inspired to play. Notably though, we find that this also is no longer a universal rule.
What casinos found over the years is that people walking down the busy aisles were frequently on the way to somewhere else. If they played slot machine games at all, they would simply put in their loose change because they happened to be walking by. Win or lose, they would very often not stop to keep playing. And the last thing a casino wants is for someone to win a jackpot by playing only a few coins and then not stay to put it all back in!
These days, casinos are constantly changing their philosophy about where to place the loose slot machine games.