Books have been written on this matter, and the controversy and interchanges about where the "hot" video slots are placed in the casino are still ongoing – more than 60 years after slots were first placed in casinos.
The quintessential rule is that the very best slot machine games were installed just inside the main doorway of the casino; so that folks going by would see jackpot winners and be possessed to come into the casino … play. Our sentiment is that this is definitely no longer so.
Almost all of the major casinos today are super-colossal complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ one armed bandits near to any doors.
Yet another classic rule is that loose slots are located on the major aisles in the casinos, again so that more potential players could see winning jackpots and be motivated to play. Nonetheless, 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 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 perspective about where to place the loose one armed bandits.