Books have been stated on this matter, and the bickering and feuds about where the "hot" slot machines are positioned in a casino are still rampant – over 60 yrs after one armed bandits were first installed in gambling dens.
The traditional rule is that the superior slots were positioned just inside the main entrance of the casino; so that fun seekers going by would be able to see jackpot winners and be convinced to come unto the gambling floor … play. Our disposition is that this is definitely no longer true.
Most of the mega casinos nowadays are oversized complexes and you can no longer see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slot machine games near any exits.
An additional classic rule is that loose slot machines are located on the major aisles inside the casinos, again so that more people could see winning jackpots and be energized to play. Importantly 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 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!
In recent times, casinos are constantly changing their perspective about where to place the loose slot games.