Books have been written on this item, and the disquiet and face-offs about where the "hot" slot machines are located in the casino are still raging – over 60 yrs after the slots were 1st placed in gambling dens.
The traditional rule is that the superior one armed bandits were positioned just inside the main door of the casino; so that individuals walking by would be able to see actual jackpot winners and be possessed to come unto the gaming floor … play. Our attitude is that this is not so anymore.
The great majority of the major casinos presently are enormous complexes and you can no longer see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ one armed bandits close-by any doors.
Yet another classic rule is that loose slot machines are located on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be roused 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 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 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!
These days, casinos are constantly changing their perspective about where to place the loose slot machines.