Books have been said on this matter, and the conflict and disharmony about where the "hot" video slots are installed in a casino are still intense – 60 years after slot games were first installed in the casinos.
The standard rule is that the more favourable slot machines were installed just inside the main foyer of the casino; so that people walking by would be able to see real jackpot winners … be attracted to come unto the gaming floor and play. Our disposition is that this is definitely no longer so.
Practically all of the large casinos nowadays are giant complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machine games close-by any doorways.
Another traditional rule is that loose slot machine games are positioned on the major aisles inside the casinos, again so that more fun seekers could see winning jackpots and be encouraged to play. Importantly however, 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 the 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 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!
In recent times, casinos are constantly changing their philosophy about where to place the loose slots.