Books have been written on this issue, and the debates and face-offs about where the "hot" slot machines are positioned in a casino are still there – more than sixty yrs after slot machines were first placed in gambling houses.
The quintessential rule is that the most favorable slot games were placed just inside the main doorway of the casino; so that potential gamblers walking by would see real jackpot winners and be enticed to come unto the gaming floor and play. Our leaning is that this is definitely no longer so.
Many of the major casinos nowadays are super-colossal complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to situate the ‘loose’ slot machine games close-by any of the doors.
An additional classic rule is that loose one armed bandits are put on the major aisles in the casinos, again so that more potential players could see winning jackpots and be inspired to play. Notably 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 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 machine games.