Books have been said on this subject, and the controversy and arguments about where the "hot" slot machines are located in a casino are still ongoing – over 60 yrs after slot machine games were 1st added to the gaming floor in gambling dens.
The quintessential rule is that the better slots were put just inside the main doorway of the casino; so that potential gamblers passing by would be able to see jackpot winners … be mesmerized enough to come into the casino and play. Our reckoning is that this is definitely no longer the case.
Almost all of the mega casinos today are super-colossal complexes … you can no longer see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slot games in close proximity to any doorways.
An additional standard rule is that loose slot machine games are located on the major aisles in the casinos, again so that more potential players could see winning jackpots and be roused to play. Notably however, 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 one armed bandits 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!
In recent times, casinos are constantly changing their perspective about where to place the loose one armed bandits.