Books have been stated on this issue, and the disquiet and ruckus about where the "hot" slots are placed in a casino are still happening – sixty yrs after the slot machines were 1st added to the gaming floor in casinos.
The traditional rule is that the very best slots were installed just inside the main door of the casino; so that potential players passing by would see actual jackpot winners and be keen enough to come into the casino … play. Our inference is that this is not so anymore.
Almost all of the mega casinos these days are gigantic complexes … now you can’t see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ slot machines near any exits.
Yet another standard rule is that loose slot machine games are placed on the major aisles in the casinos, again so that more fun seekers could see winning jackpots and be galvanized to play. Notably however, 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 one armed bandits 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 philosophy about where to place the loose slots.