Books have been set forth on this matter, and the debates and disharmony about where the "hot" slot games are placed in a casino are still ongoing – 60 years after the slots were 1st placed in gambling dens.
The classic rule is that the most favorable slots were located just inside the main entrance of the casino; so that fun seekers walking by would be able to see actual jackpot winners … be inspired to come unto the gaming floor … play. Our inference is that this is definitely no longer the case.
The great majority of the big name casinos these days are herculean complexes and you no longer can see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ one armed bandits in close proximity to any doorways.
Another traditional rule is that loose slot games are installed on the major aisles in the casinos, again so that more potential players could see winning jackpots and be galvanized to play. Interestingly though, we find that this also is not 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 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.