Books have been stated on this topic, and the disquiet and ruckus about where the "hot" video slots are installed in a casino are still passionate – over sixty years after slot machines were first placed in the casinos.
The quintessential rule is that the most favorable slot machines were put just inside the entrance of the casino; so that folks passing by would see actual jackpot winners … be keen enough to come inside and play. Our speculation is that this is no longer true.
Just about all of the large casinos presently are humongous complexes and now you can’t see inside from the sidewalk, so there’s no longer a reason to have the ‘loose’ one armed bandits close to any entrances.
Another standard rule is that loose slot machines are placed on the major aisles in the casinos, again so that more folks could see winning jackpots and be galvanized to play. Importantly however, 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 slot machine 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.