Volumes have been stated on this matter, and the debates and arguments about where the "hot" slot machines are installed in the casino are still taking place – sixty years after the slots were 1st placed in gambling dens.
The traditional rule is that the better slot machines were installed just inside the main entryway of the casino; so that folks passing by would be able to see actual jackpot winners and be enthralled to come unto the gaming floor and play. Our point of view is that this is no longer the case.
Nearly all of the major casinos presently are gigantic complexes … you can no longer see inside from the sidewalk, so there’s no longer a reason to place the ‘loose’ slot games near to any doorways.
An additional classic rule is that loose slot machines are installed on the major aisles inside the casinos, again so that more people could see winning jackpots and be influenced to play. Interestingly 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!
These days, casinos are constantly changing their philosophy about where to place the loose slots.