Books have been stated on this topic, and the bickering and discourse about where the "hot" slot games are installed in the casino are still there – sixty yrs after the slots were first placed in casinos.
The quintessential rule is that the superior slot machine games were positioned just inside the main door of the casino; so that folks going by would be able to see actual jackpot winners and be enticed to come unto the gambling floor … play. Our resolution is that this is definitely no longer the case.
The great majority of the mega casinos these days are magnificent complexes and now you can’t see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slot machines in close proximity to any exits.
An additional traditional rule is that loose one armed bandits are positioned on the major aisles inside the casinos, again so that more persons could see winning jackpots and be influenced to play. Nonetheless, 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 the 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 perspective about where to place the loose one armed bandits.