Books have been stated on this topic, and the controversy and interchanges about where the "hot" video slots are located in the casino are still on-going – over 60 years after the slot machines were 1st placed in casinos.
The classic rule is that the better slot machine games were positioned just inside the main entryway of the casino; so that folks going by would see real jackpot winners and be influenced to come into the casino … play. Our leaning is that this is no longer the case.
Almost all of the big name casinos presently are humongous complexes … you can no longer see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ one armed bandits near to any exits.
Another classic rule is that loose slots are located on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be inspired 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 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!
Nowadays, casinos are constantly changing their perspective about where to place the loose slot games.