Books have been written on this topic, and the bickering and discussion about where the "hot" one armed bandits are positioned in a casino are still happening – over sixty years after slot machine games were 1st placed in gambling houses.
The quintessential rule is that the better one armed bandits were put just inside the main foyer of the casino; so that folks walking by would be able to see real jackpot winners and be attracted to come into the casino and play. Our assessment is that this is definitely no longer so.
Many of the large casinos today are immense complexes … now you can’t see inside from the sidewalk, so there is no longer a reason to put the ‘loose’ slot machines in close proximity to any doors.
An additional traditional rule is that loose slot machine games are placed on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be roused to play. Importantly 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 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 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!
These days, casinos are constantly changing their perspective about where to place the loose slot machines.