Books have been written on this topic, and the debates and face-offs about where the "hot" slots are located in a casino are still there – over 60 years after the slot machines were 1st installed in casinos.
The traditional rule is that the better one armed bandits were installed just inside the main door of the casino; so that casino fanatics walking by would be able to see actual jackpot winners … be enticed to come unto the gaming floor and play. Our determination is that this is no longer true.
Nearly all of the large casinos nowadays are grand complexes … you no longer can see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slots near to any doorways.
Yet another traditional rule is that loose slots are located on the major aisles in the casinos, again so that more folks could see winning jackpots and be inspired to play. Notably however, 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 slots 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!
Nowadays, casinos are constantly changing their perspective about where to place the loose slots.