Volumes have been written on this matter, and the bickering and ruckus about where the "hot" one armed bandits are placed in the casino are still on-going – more than sixty years after slot machines were 1st installed in gambling houses.
The classic rule is that the very best slots were located just inside the door of the casino; so that persons walking by would be able to see actual jackpot winners and be possessed to come unto the gambling floor and play. Our inclination is that this is not so anymore.
Nearly all of the major casinos nowadays are mammoth complexes and you can no longer see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machine games close-by any of the doors.
An additional traditional rule is that loose slot machines are installed on the major aisles in the casinos, again so that more folks could see winning jackpots and be energized to play. Nonetheless, 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 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 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose one armed bandits.