Volumes have been written on this subject, and the conflict and discussion about where the "hot" slot machines are placed in the casino are still ongoing – over 60 yrs after slots were 1st added to the gaming floor in gambling houses.
The standard rule is that the superior slot machine games were located just inside the main foyer of the casino; so that potential players passing by would be able to see jackpot winners and be smitten to come unto the gambling floor and play. Our attitude is that this is no longer true.
Nearly all of the major casinos nowadays are colossal complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to situate the ‘loose’ slot games close-by any doors.
An additional standard rule is that loose slot machines are placed on the major aisles inside the casinos, again so that more persons could see winning jackpots and be motivated to play. However, 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 slot machine 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 philosophy about where to place the loose slot machine games.