Books have been written on this matter, and the contention and discord about where the "hot" slot games are installed in a casino are still there – over sixty yrs after one armed bandits were first placed in casinos.
The standard rule is that the best slots were placed just inside the entry of the casino; so that everyone walking by would see jackpot winners and be impressed enough to come into the casino and play. Our observation is that this is no longer true.
Practically all of the mega casinos today are giant complexes … it is not possible to see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slots close-by any entrances or exits.
Yet another traditional rule is that loose slot machine games are positioned on the major aisles inside the casinos, again so that more people could see winning jackpots and be inspired to play. Notably 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 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 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 perspective about where to place the loose slot games.