Books have been written on this matter, and the debates and disharmony about where the "hot" slot games are placed in the casino are still on-going – sixty yrs after the slot machines were first placed in the casinos.
The quintessential rule is that the best slot games were put just inside the main foyer of the casino; so that people walking by would see jackpot winners … be baited to come into the casino … play. Our conclusion is that this is no longer true.
Many of the big name casinos presently are humongous complexes … you no longer can see inside from the sidewalk, so there is no longer a reason to put the ‘loose’ slot machines close-by any of the doors.
Another standard rule is that loose slot games are positioned on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be inspired to play. Nonetheless, 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 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 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!
Today, casinos are constantly changing their philosophy about where to place the loose one armed bandits.