Volumes have been written on this matter, and the controversy and ruckus about where the "hot" slots are installed in the casino are still on-going – more than 60 yrs after slots were 1st installed in gambling houses.
The traditional rule is that the more favourable slots were put just inside the door of the casino; so that everyone passing by would see actual jackpot winners and be challenged to come inside … play. Our viewpoint is that this is not so anymore.
Nearly all of the big name casinos today are herculean complexes and you no longer can see inside from the sidewalk, so there’s no longer a reason to situate the ‘loose’ slot machines close-by any entrances.
An additional traditional rule is that loose slot machines are positioned on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be encouraged to play. Notably though, 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 the slot machines 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 slot machines.