Books have been written on this topic, and the debates and disharmony about where the "hot" slots are positioned in a casino are still passionate – sixty yrs after the slots were first placed in gambling houses.
The quintessential rule is that the more favourable slot machine games were put just inside the main entryway of the casino; so that people walking by would see jackpot winners and be intrigued enough to come inside … play. Our opinion is that this is definitely no longer so.
Nearly all of the major casinos these days are huge complexes … now you can’t see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slots close to any doorways.
Yet another standard rule is that loose slot machines are positioned on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be influenced to play. Importantly though, we find that this also isn’t 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 very 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 slot machines.