Volumes have been written on this matter, and the bickering and disagreement about where the "hot" slot games are installed in the casino are still taking place – sixty yrs after slots were first installed in casinos.
The classic rule is that the most favorable one armed bandits were located just inside the main entry of the casino; so that folks going by would be able to see actual jackpot winners and be drawn to come into the casino … play. Our deduction is that this is no longer the case.
The majority of the big name casinos presently are herculean complexes and now you can’t see inside from the sidewalk, so there’s no longer a reason to have the ‘loose’ slot machines near to any exits.
An additional traditional rule is that loose slot machines are located on the major aisles in the casinos, again so that more folks could see winning jackpots and be motivated to play. Importantly though, we find that this also isn’t 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 slots 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slots.