Books have been stated on this matter, and the contention and squabbling about where the "hot" slot machine games are located in the casino are still passionate – more than 60 yrs after slot machine games were 1st placed in casinos.
The traditional rule is that the best slot machines were put just inside the entry of the casino; so that everyone passing by would be able to see jackpot winners … be inspired to come inside and play. Our interpretation is that this is definitely no longer true.
Nearly all of the large casinos today are behemothic complexes and now you can’t see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slot machines in close proximity to any exits.
Another standard rule is that loose one armed bandits are put on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be energized to play. Notably though, 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 one armed bandits 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!
Nowadays, casinos are constantly changing their perspective about where to place the loose slot games.