Books have been written on this topic, and the contention and arguments about where the "hot" video slots are located in a casino are still taking place – more than sixty years after slots were first placed in casinos.
The quintessential rule is that the best slot games were put just inside the main entrance of the casino; so that potential players walking by would be able to see real jackpot winners … be attracted to come unto the gaming floor … play. Our sneaking suspicion is that this is no longer the case.
Practically all of the mega casinos presently are super-colossal complexes and it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to put the ‘loose’ slot machines near any doorways.
Another traditional rule is that loose slots are put on the major aisles inside the casinos, again so that more persons could see winning jackpots and be galvanized to play. Importantly 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 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slot machine games.