Books have been written on this matter, and the debates and discussion about where the "hot" slots are installed in a casino are still raging – more than 60 yrs after the slot machines were first installed in gambling dens.
The traditional rule is that the more favourable slot games were positioned just inside the main door of the casino; so that potential gamblers going by would be able to see actual jackpot winners … be aroused to come unto the gaming floor and play. Our standpoint is that this is definitely no longer so.
Nearly all of the mega casinos today are gigantic complexes … now you can’t see inside from the sidewalk, so there is no longer a reason to place the ‘loose’ slot machines close to any entrances.
Yet another standard rule is that loose slot machines are installed on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be inspired to play. Interestingly 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 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 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!
Nowadays, casinos are constantly changing their philosophy about where to place the loose one armed bandits.