Books have been stated on this item, and the bickering and disharmony about where the "hot" slot games are located in the casino are still ongoing – over 60 yrs after slot games were 1st placed in casinos.
The quintessential rule is that the superior slot games were positioned just inside the main entry of the casino; so that people passing by would see real jackpot winners … be possessed to come into the casino … play. Our observation is that this is definitely no longer the case.
The majority of the large casinos today are oversized complexes and now you can’t see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ slot machine games in close proximity to any of the doors.
An additional standard rule is that loose slots are placed on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be inspired to play. Importantly though, 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 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!
These days, casinos are constantly changing their philosophy about where to place the loose slot machines.