Books have been set forth on this topic, and the bickering and disagreement about where the "hot" one armed bandits are installed in the casino are still on-going – more than sixty yrs after slot games were 1st placed in gambling dens.
The quintessential rule is that the best slot games were put just inside the main entry of the casino; so that persons passing by would be able to see actual jackpot winners and be aroused to come unto the gaming floor … play. Our speculation is that this is definitely no longer so.
Most of the large casinos presently are huge complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to put the ‘loose’ slot games close-by any exits.
An additional standard rule is that loose one armed bandits are installed on the major aisles inside the casinos, again so that more folks could see winning jackpots and be influenced to play. Notably though, we find that this also isn’t 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 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 perspective about where to place the loose one armed bandits.