Books have been written on this matter, and the bickering and discussion about where the "hot" slot machine games are located in a casino are still passionate – sixty years after slot games were 1st added to the gaming floor in gambling houses.
The quintessential rule is that the most favorable one armed bandits were located just inside the main door of the casino; so that potential players passing by would be able to see real jackpot winners and be keen enough to come into the casino … play. Our standpoint is that this is definitely no longer true.
Nearly all of the mega casinos presently are herculean complexes … it is not possible to see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slot machine games close to any entrances.
An additional standard rule is that loose slot machine games are located on the major aisles in the casinos, again so that more persons could see winning jackpots and be encouraged 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 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 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 games.