Volumes have been said on this topic, and the contention and discourse about where the "hot" slot machines are installed in the casino are still taking place – over 60 yrs after slot games were 1st placed in casinos.
The classic rule is that the best slot machines were put just inside the entrance of the casino; so that persons passing by would be able to see real jackpot winners and be smitten to come unto the gaming floor … play. Our sneaking suspicion is that this is definitely no longer true.
The majority of the mega casinos nowadays are huge complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slots close-by any entrances or exits.
Another standard rule is that loose one armed bandits are put on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be motivated to play. Notably however, 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 one armed bandits 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!
These days, casinos are constantly changing their perspective about where to place the loose one armed bandits.