Books have been said on this topic, and the debates and feuds about where the "hot" one armed bandits are positioned in the casino are still intense – more than 60 yrs after slots were first placed in casinos.
The quintessential rule is that the most favorable slot machines were located just inside the main foyer of the casino; so that people walking by would be able to see actual jackpot winners and be attracted to come into the casino … play. Our stance is that this is definitely no longer the case.
Most of the mega casinos presently are immense complexes and it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ one armed bandits close-by any entrances or exits.
Yet another standard rule is that loose slots are located on the major aisles in the casinos, again so that more people could see winning jackpots and be roused to play. Interestingly though, 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!
In recent times, casinos are constantly changing their perspective about where to place the loose slots.