Books have been stated on this subject, and the bickering and disharmony about where the "hot" slot machines are installed in the casino are still rampant – 60 years after the slot machines were 1st added to the gaming floor in gambling dens.
The traditional rule is that the superior slot machines were placed just inside the main door of the casino; so that potential gamblers passing by would see actual jackpot winners … be stimulated to come inside and play. Our observation is that this is definitely no longer the case.
Practically all of the mega casinos nowadays are herculean complexes and you can no longer see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slots in close proximity to any of the doors.
Yet another standard rule is that loose slots are put on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be motivated to play. Importantly however, we find that this also is not 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 slot machine games.