Books have been written on this issue, and the debates and feuds about where the "hot" slot machines are positioned in the casino are still intense – over 60 yrs after slot games were 1st installed in casinos.
The quintessential rule is that the better slot machines were positioned just inside the main doorway of the casino; so that individuals going by would be able to see jackpot winners and be titillated to come unto the gaming floor … play. Our inclination is that this is definitely no longer the case.
The great majority of the mega casinos these days are monstrous complexes … you can no longer see inside from the sidewalk, so there’s no longer a reason to have the ‘loose’ slot machines near any exits.
Another standard rule is that loose slot machine games are located on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be roused to play. Notably however, 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 one armed bandits 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.