Books have been set forth on this matter, and the conflict and disagreement about where the "hot" slots are installed in a casino are still ongoing – 60 yrs after slots were first added to the gaming floor in casinos.
The classic rule is that the best slot machines were located just inside the main door of the casino; so that folks walking by would be able to see real jackpot winners … be stirred to come unto the gaming floor … play. Our opinion is that this is definitely no longer true.
Almost all of the large casinos these days are immense complexes and you no longer can see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slot games close-by any entrances.
An additional traditional rule is that loose slots are located on the major aisles in the casinos, again so that more potential gamblers could see winning jackpots and be inspired to play. Interestingly 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 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.