Books have been written on this item, and the disquiet and discussion about where the "hot" slot machine games are placed in a casino are still on-going – more than sixty yrs after the slot machines were first placed in the casinos.
The quintessential rule is that the superior slot games were placed just inside the main door of the casino; so that individuals passing by would be able to see actual jackpot winners and be stirred to come inside and play. Our standpoint is that this is definitely no longer so.
Just about all of the big name casinos nowadays are huge complexes … it’s no longer possible to see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ slots near to any of the doors.
An additional traditional rule is that loose one armed bandits are located on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be inspired 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 slot games 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!
Today, casinos are constantly changing their perspective about where to place the loose slot games.