Books have been said on this item, and the bickering and feuds about where the "hot" slot machines are positioned in a casino are still on-going – over sixty years after slot games were first added to the gaming floor in the casinos.
The classic rule is that the better one armed bandits were installed just inside the door of the casino; so that potential players going by would be able to see jackpot winners and be influenced to come into the casino and play. Our reasoning is that this is definitely no longer so.
Almost all of the large casinos nowadays are jumbo complexes … it’s no longer possible to see inside from the sidewalk, so there is no longer a reason to position the ‘loose’ one armed bandits near to any entrances.
An additional standard rule is that loose one armed bandits are placed on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be motivated to play. Notably 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 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 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!
These days, casinos are constantly changing their perspective about where to place the loose slots.