Volumes have been said on this topic, and the controversy and disagreement about where the "hot" slot machine games are placed in a casino are still on-going – over sixty yrs after the slot machines were 1st added to the gaming floor in gambling houses.
The quintessential rule is that the superior slots were installed just inside the main doorway of the casino; so that potential gamblers going by would be able to see actual jackpot winners and be inspired to come inside … play. Our assessment is that this is no longer true.
Practically all of the big name casinos these days are colossal complexes … it is not possible to see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slot machine games near to any exits.
Another standard rule is that loose slots are placed on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be energized 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 slot 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!
These days, casinos are constantly changing their philosophy about where to place the loose slot machines.