Books have been set forth on this topic, and the controversy and discussion about where the "hot" one armed bandits are placed in a casino are still rampant – more than 60 yrs after slot machine games were 1st placed in gambling dens.
The standard rule is that the most favorable one armed bandits were put just inside the main doorway of the casino; so that everyone going by would see real jackpot winners … be attracted to come unto the gambling floor … play. Our philosophy is that this is definitely no longer true.
Just about all of the mega casinos these days are gigantic complexes and it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to put the ‘loose’ one armed bandits near to any entrances.
Another traditional rule is that loose slots are installed on the major aisles inside the casinos, again so that more folks could see winning jackpots and be encouraged to play. Interestingly 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 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 very 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 perspective about where to place the loose slot machines.