Books have been stated on this issue, and the contention and arguments about where the "hot" slot machines are installed in the casino are still intense – over sixty yrs after one armed bandits were 1st placed in the casinos.
The standard rule is that the best slot machines were put just inside the door of the casino; so that everyone going by would see real jackpot winners and be possessed to come unto the gaming floor … play. Our assessment is that this is definitely no longer true.
Just about all of the big name casinos these days are oversized complexes … it is not possible to see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ one armed bandits close to any entrances.
Another traditional rule is that loose slot machine games are placed on the major aisles in the casinos, again so that more folks could see winning jackpots and be galvanized to play. Interestingly 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.