Volumes have been set forth on this topic, and the bickering and discord about where the "hot" one armed bandits are placed in a casino are still raging – sixty years after slot machines were first placed in gambling houses.
The quintessential rule is that the very best slots were positioned just inside the main entry of the casino; so that everyone going by would be able to see real jackpot winners and be possessed to come unto the gaming floor and play. Our reckoning is that this is definitely no longer so.
Practically all of the major casinos nowadays are giant complexes and it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ one armed bandits in close proximity to any doorways.
Another traditional rule is that loose one armed bandits are installed on the major aisles inside the casinos, again so that more people could see winning jackpots and be inspired to play. Notably though, we find that this also isn’t a universal rule any more.
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 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 very 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slot games.