Books have been said on this topic, and the controversy and feuds about where the "hot" one armed bandits are installed in the casino are still intense – sixty yrs after slot games were 1st installed in casinos.
The standard rule is that the best slot machines were placed just inside the entrance of the casino; so that everyone walking by would be able to see actual jackpot winners … be challenged to come inside … play. Our leaning is that this is no longer the case.
The great majority of the large casinos today are humongous complexes … you can no longer see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slot games close to any of the doors.
Another traditional rule is that loose slot machine games are placed on the major aisles inside the casinos, again so that more folks could see winning jackpots and be encouraged 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 the 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 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slot games.