Books have been written on this topic, and the debates and disagreement about where the "hot" slot machine games are installed in a casino are still bubbling – 60 years after the slot machines were first installed in gambling dens.
The traditional rule is that the more favourable slots were installed just inside the main entry of the casino; so that fun seekers walking by would be able to see jackpot winners … be intrigued enough to come inside and play. Our theory is that this is definitely no longer so.
Practically all of the large casinos today are grand complexes … you no longer can see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ one armed bandits close to any exits.
Another classic rule is that loose one armed bandits are positioned on the major aisles in the casinos, again so that more people could see winning jackpots and be inspired 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 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slot machine games.