Books have been stated on this subject, and the conflict and ruckus about where the "hot" slot machines are located in the casino are still there – over 60 yrs after the slots were first placed in gambling dens.
The standard rule is that the superior slot machines were put just inside the main doorway of the casino; so that casino fanatics walking by would be able to see actual jackpot winners … be aroused to come unto the gaming floor and play. Our deduction is that this is no longer true.
The majority of the major casinos these days are massive complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ one armed bandits near to any entrances.
Yet another traditional rule is that loose slot machines are located on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be motivated to play. Interestingly though, we find that this also is not 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 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 philosophy about where to place the loose slots.