Books have been stated on this matter, and the disquiet and feuds about where the "hot" slot machine games are located in a casino are still on-going – 60 years after the slot machines were first placed in casinos.
The quintessential rule is that the most favorable slot machine games were located just inside the main entrance of the casino; so that fun seekers walking by would see real jackpot winners and be enticed to come unto the gambling floor and play. Our conviction is that this is not so anymore.
Just about all of the big name casinos presently are enormous complexes and it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to have the ‘loose’ slot games near to any doors.
Yet another standard rule is that loose slot machine games are positioned on the major aisles inside the casinos, again so that more persons could see winning jackpots and be inspired to play. Nonetheless, 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!
These days, casinos are constantly changing their philosophy about where to place the loose slots.