Volumes have been written on this matter, and the disquiet and arguments about where the "hot" slots are installed in the casino are still ongoing – more than sixty years after the slot machines were 1st placed in casinos.
The standard rule is that the superior slot machines were put just inside the main entryway of the casino; so that people going by would be able to see real jackpot winners … be influenced to come unto the gaming floor … play. Our inclination is that this is no longer the case.
Most of the mega casinos today are super-colossal complexes … you can no longer see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slot machines near any exits.
Yet another standard rule is that loose slot machine games are placed on the major aisles in the casinos, again so that more potential players could see winning jackpots and be galvanized to play. Notably however, 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 slots 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!
In recent times, casinos are constantly changing their perspective about where to place the loose slot games.