Books have been stated on this matter, and the disquiet and squabbling about where the "hot" video slots are placed in the casino are still there – over 60 years after the slot machines were 1st placed in casinos.
The standard rule is that the very best slot machines were put just inside the entrance of the casino; so that fun seekers passing by would be able to see jackpot winners and be infatuated enough to come unto the gaming floor … play. Our inference is that this is definitely no longer the case.
The majority of the mega casinos these days are grand complexes and now you can’t see inside from the sidewalk, so there is no longer a reason to have the ‘loose’ slots close-by any exits.
Yet another classic rule is that loose slots are placed on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be energized to play. Importantly though, we find that this also is not a universal rule any more.
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 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 philosophy about where to place the loose slot games.