Books have been written on this issue, and the conflict and squabbling about where the "hot" one armed bandits are installed in a casino are still on-going – sixty yrs after slot machines were first installed in gambling dens.
The classic rule is that the better slots were located just inside the main entrance of the casino; so that people passing by would be able to see real jackpot winners and be aroused to come into the casino and play. Our frame of mind is that this is definitely no longer so.
Practically all of the large casinos these days are massive complexes and now you can’t see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ slot games near to any entrances or exits.
Yet another classic rule is that loose slot machine games are put on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be encouraged to play. Importantly 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 slot games 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!
Nowadays, casinos are constantly changing their perspective about where to place the loose slots.