Books have been said on this subject, and the disquiet and arguments about where the "hot" slot machine games are installed in the casino are still ongoing – sixty yrs after slot machine games were first installed in gambling dens.
The classic rule is that the superior slot machines were installed just inside the main entry of the casino; so that potential gamblers walking by would see real jackpot winners … be smitten to come inside and play. Our theorem is that this is not so anymore.
The great majority of the large casinos these days are titanic complexes … now you can’t see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slot machine games close to any doors.
Another classic rule is that loose slot machine games are placed on the major aisles in the casinos, again so that more potential gamblers could see winning jackpots and be influenced 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 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 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!
These days, casinos are constantly changing their perspective about where to place the loose slot games.