Books have been said on this issue, and the bickering and discourse about where the "hot" slots are installed in the casino are still raging – over sixty yrs after slot games were 1st placed in casinos.
The quintessential rule is that the very best slot machines were installed just inside the main foyer of the casino; so that everyone passing by would see real jackpot winners and be possessed to come unto the gambling floor … play. Our sneaking suspicion is that this is no longer the case.
Practically all of the major casinos nowadays are titanic complexes … it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ slot machines near to any entrances or exits.
Another standard rule is that loose one armed bandits are put on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be encouraged to play. Notably however, 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 the slot machines 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!
Nowadays, casinos are constantly changing their philosophy about where to place the loose slot machines.
