Volumes have been stated on this topic, and the debates and disagreement about where the "hot" one armed bandits are placed in a casino are still on-going – over 60 yrs after slot machine games were 1st placed in casinos.
The classic rule is that the more favourable slots were put just inside the main entryway of the casino; so that potential gamblers walking by would be able to see real jackpot winners and be inspired to come inside … play. Our view is that this is definitely no longer so.
The majority of the major casinos presently are gigantic complexes and you no longer can see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machines close-by any doors.
Yet another traditional rule is that loose slots are positioned on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be encouraged to play. Nonetheless, 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 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!
Today, casinos are constantly changing their philosophy about where to place the loose slot games.
