Books have been said on this matter, and the controversy and discord about where the "hot" one armed bandits are installed in a casino are still bubbling – more than 60 yrs after the slot machines were 1st placed in the casinos.
The quintessential rule is that the most favorable one armed bandits were put just inside the main entrance of the casino; so that potential gamblers passing by would be able to see jackpot winners and be baited to come inside … play. Our opinion is that this is definitely no longer so.
Nearly all of the major casinos today are behemothic complexes and it is not possible to see inside from the sidewalk, so there is no longer a reason to situate the ‘loose’ slot machines close-by any doorways.
Another classic rule is that loose slot machine games are installed on the major aisles in the casinos, again so that more potential players could see winning jackpots and be influenced to play. Importantly however, 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 one armed bandits 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!
Today, casinos are constantly changing their philosophy about where to place the loose slot machine games.