Books have been written on this topic, and the contention and disharmony about where the "hot" slot machines are located in a casino are still rampant – more than sixty yrs after the slot machines were 1st installed in casinos.
The traditional rule is that the most favorable slots were placed just inside the main foyer of the casino; so that potential gamblers going by would see real jackpot winners and be enticed to come into the casino … play. Our resolve is that this is no longer true.
Practically all of the large casinos today are super-colossal complexes and it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ slots close to any doorways.
Yet another standard rule is that loose slots are installed on the major aisles in the casinos, again so that more people 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 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 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!
These days, casinos are constantly changing their philosophy about where to place the loose slot machine games.