Books have been written on this matter, and the contention and ruckus about where the "hot" one armed bandits are located in the casino are still there – sixty yrs after slot machines were first added to the gaming floor in the casinos.
The classic rule is that the very best slot machines were put just inside the main entry of the casino; so that potential players walking by would see real jackpot winners and be smitten to come unto the gambling floor … play. Our feeling is that this is definitely no longer so.
The majority of the large casinos nowadays are herculean complexes … you no longer can see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machines close to any doorways.
Another classic rule is that loose slot games are placed on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be motivated to play. Importantly 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 slot machines 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!
Today, casinos are constantly changing their perspective about where to place the loose slots.