Books have been said on this topic, and the contention and discord about where the "hot" slots are installed in the casino are still ongoing – sixty yrs after the slot machines were 1st placed in gambling houses.
The classic rule is that the best slot machine games were put just inside the main entrance of the casino; so that potential gamblers passing by would see jackpot winners and be infatuated enough to come unto the gaming floor … play. Our sneaking suspicion is that this is definitely no longer so.
Almost all of the mega casinos today are mammoth complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slot machine games close-by any entrances or exits.
Yet another classic rule is that loose slot games are positioned on the major aisles inside the casinos, again so that more folks could see winning jackpots and be galvanized to play. Nonetheless, 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 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 perspective about where to place the loose slot games.