Books have been written on this topic, and the contention and ruckus about where the "hot" slot machines are positioned in the casino are still ongoing – over 60 years after slot games were 1st installed in casinos.
The quintessential rule is that the most favorable one armed bandits were placed just inside the main door of the casino; so that persons going by would be able to see jackpot winners … be stirred to come unto the gaming floor … play. Our theorem is that this is definitely no longer the case.
Nearly all of the mega casinos presently are magnificent complexes … now you can’t see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slot machines close to any doors.
Yet another standard rule is that loose slot machine games are positioned on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be inspired 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 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 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 slots.