Books have been said on this subject, and the conflict and ruckus about where the "hot" slot machine games are installed in a casino are still intense – sixty yrs after slots were first installed in gambling dens.
The standard rule is that the very best slots were located just inside the main entry of the casino; so that potential players going by would see actual jackpot winners … be influenced to come unto the gambling floor and play. Our deduction is that this is no longer true.
Most of the mega casinos these days are herculean complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ slot machines near any doorways.
Yet another standard rule is that loose slots are located on the major aisles in the casinos, again so that more potential gamblers could see winning jackpots and be encouraged to play. Importantly 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slot games.