Volumes have been set forth on this item, and the bickering and ruckus about where the "hot" slots are placed in a casino are still happening – more than sixty yrs after slots were 1st placed in casinos.
The classic rule is that the superior one armed bandits were installed just inside the main door of the casino; so that folks walking by would be able to see actual jackpot winners … be aroused to come unto the gambling floor and play. Our presumption is that this is definitely no longer so.
The majority of the mega casinos these days are immense complexes and you no longer can see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machine games close-by any doors.
Another traditional rule is that loose slot machines are placed on the major aisles inside the casinos, again so that more folks could see winning jackpots and be roused to play. Interestingly 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 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 philosophy about where to place the loose slot machines.