Books have been set forth on this subject, and the contention and discourse about where the "hot" slot machines are located in a casino are still rampant – sixty years after the slots were 1st added to the gaming floor in gambling dens.
The quintessential rule is that the very best slot games were located just inside the entrance of the casino; so that persons walking by would see jackpot winners and be challenged to come unto the gaming floor … play. Our attitude is that this is definitely no longer true.
Practically all of the major casinos these days are immense complexes and you can no longer see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slots near to any entrances or exits.
Another classic rule is that loose slots are put on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be encouraged to play. Importantly though, 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 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!
Nowadays, casinos are constantly changing their perspective about where to place the loose slot machines.