Books have been stated on this matter, and the conflict and interchanges about where the "hot" slot machines are installed in the casino are still on-going – over 60 years after one armed bandits were 1st added to the gaming floor in casinos.
The classic rule is that the most favorable slots were positioned just inside the main doorway of the casino; so that everyone walking by would be able to see jackpot winners and be mesmerized enough to come unto the gaming floor … play. Our disposition is that this is definitely no longer the case.
Many of the major casinos these days are grand complexes … you no longer can see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slot games near any entrances or exits.
Another classic rule is that loose one armed bandits are placed on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be encouraged to play. Notably however, 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 the slot machines 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!
Today, casinos are constantly changing their perspective about where to place the loose one armed bandits.