Books have been stated on this item, and the debates and discussion about where the "hot" one armed bandits are located in a casino are still passionate – 60 yrs after one armed bandits were first placed in gambling dens.
The classic rule is that the most favorable slot games were placed just inside the main foyer of the casino; so that everyone walking by would be able to see real jackpot winners … be enticed to come into the casino and play. Our conviction is that this is not so anymore.
Almost all of the major casinos nowadays are herculean complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slot machines near to any doors.
An additional standard rule is that loose slot machine games are placed on the major aisles in the casinos, again so that more people could see winning jackpots and be motivated to play. Notably 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 the 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!
Today, casinos are constantly changing their philosophy about where to place the loose slots.