Books have been stated on this issue, and the bickering and discord about where the "hot" one armed bandits are positioned in a casino are still taking place – more than sixty years after slot games were 1st placed in the casinos.
The standard rule is that the best slot games were positioned just inside the entry of the casino; so that people going by would see real jackpot winners and be baited to come into the casino … play. Our feeling is that this is definitely no longer so.
Nearly all of the major casinos nowadays are enormous complexes … it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ slots close-by any doorways.
An additional standard rule is that loose slot machine games are located on the major aisles in the casinos, again so that more persons could see winning jackpots and be inspired to play. Notably though, 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 machine 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!
Today, casinos are constantly changing their perspective about where to place the loose slot machines.