Books have been written on this subject, and the controversy and discord about where the "hot" slots are positioned in the casino are still happening – over 60 years after one armed bandits were first installed in gambling houses.
The standard rule is that the very best slot games were installed just inside the main doorway of the casino; so that everyone walking by would see jackpot winners and be aroused to come unto the gambling floor and play. Our conclusion is that this is not so anymore.
The great majority of the mega casinos these days are colossal complexes and it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ one armed bandits in close proximity to any entrances.
An additional standard rule is that loose slot machines are located on the major aisles inside the casinos, again so that more folks could see winning jackpots and be encouraged to play. Importantly though, 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!
Today, casinos are constantly changing their philosophy about where to place the loose slots.