Books have been said on this issue, and the bickering and arguments about where the "hot" slot machines are placed in a casino are still bubbling – over 60 years after slot machines were 1st placed in gambling dens.
The traditional rule is that the best one armed bandits were put just inside the main doorway of the casino; so that people going by would be able to see actual jackpot winners and be drawn to come unto the gambling floor and play. Our philosophy is that this is definitely no longer true.
Most of the mega casinos today are monstrous complexes … you no longer can see inside from the sidewalk, so there is no longer a reason to situate the ‘loose’ slot machines near any entrances or exits.
An additional traditional rule is that loose one armed bandits are positioned on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be influenced to play. Notably though, we find that this also is no longer a universal rule.
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 slot games 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!
Nowadays, casinos are constantly changing their philosophy about where to place the loose one armed bandits.