Books have been set forth on this matter, and the contention and disharmony about where the "hot" slot machines are located in a casino are still intense – more than 60 yrs after slots were first placed in casinos.
The traditional rule is that the better slot machine games were put just inside the main entrance of the casino; so that everyone walking by would be able to see real jackpot winners and be stirred to come unto the gaming floor … play. Our reasoning is that this is no longer the case.
Nearly all of the major casinos today are colossal complexes and it is not possible to see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machines in close proximity to any entrances.
Yet another standard rule is that loose slot games are put on the major aisles inside the casinos, again so that more persons could see winning jackpots and be energized to play. Importantly 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 philosophy about where to place the loose slot machine games.