Volumes have been written on this topic, and the bickering and ruckus about where the "hot" slots are positioned in the casino are still ongoing – 60 yrs after slot games were first added to the gaming floor in the casinos.
The classic rule is that the very best slot games were installed just inside the door of the casino; so that everyone going by would see jackpot winners … be possessed to come into the casino … play. Our theory is that this is no longer true.
Many of the major casinos today are humongous complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ one armed bandits in close proximity to any of the doors.
An additional classic rule is that loose slots are located on the major aisles in the casinos, again so that more people could see winning jackpots and be influenced to play. Notably though, we find that this also isn’t 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 machine 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 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!
Today, casinos are constantly changing their perspective about where to place the loose slot machines.