Books have been stated on this issue, and the contention and discord about where the "hot" one armed bandits are installed in the casino are still ongoing – 60 yrs after the slots were first installed in the casinos.
The quintessential rule is that the more favourable slot machines were positioned just inside the main entryway of the casino; so that individuals walking by would see real jackpot winners and be tempted to come unto the gaming floor … play. Our persuasion is that this is not so anymore.
The great majority of the major casinos today are magnificent complexes … you can no longer see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slots close to any entrances.
Yet another classic rule is that loose one armed bandits are located on the major aisles inside the casinos, again so that more potential gamblers could see winning jackpots and be encouraged 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 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 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 machines.