Books have been written on this matter, and the bickering and ruckus about where the "hot" slot machine games are located in a casino are still raging – 60 years after slot machine games were first placed in gambling dens.
The classic rule is that the most favorable slot machines were placed just inside the entry of the casino; so that casino fanatics going by would be able to see actual jackpot winners and be attracted to come inside … play. Our theory is that this is no longer true.
Just about all of the mega casinos these days are mammoth complexes and it is not possible to see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slots close-by any entrances.
An additional classic rule is that loose slot machines are located on the major aisles in 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 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 perspective about where to place the loose slots.