Books have been stated on this matter, and the contention and ruckus about where the "hot" slots are located in the casino are still ongoing – sixty yrs after one armed bandits were 1st added to the gaming floor in gambling dens.
The classic rule is that the very best slot machine games were located just inside the door of the casino; so that fun seekers passing by would be able to see real jackpot winners … be challenged to come into the casino … play. Our perspective is that this is no longer the case.
Many of the mega casinos nowadays are gigantic complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to situate the ‘loose’ slot machines near to any entrances or exits.
An additional classic rule is that loose slot games are put on the major aisles in the casinos, again so that more folks could see winning jackpots and be roused to play. Interestingly 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 the 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 philosophy about where to place the loose slot games.