There's a little bit of truth here, but it's mostly incorrect. Yes casinos set the odds for any individual slot machine. However the game manufacturers prepare

There's a little bit of truth here, but it's mostly incorrect. Yes casinos set the odds for any individual slot machine. However the game manufacturers prepare the games with about 5 configurations, even the loosest config will still be well into the casinos favor (it's sort of like how Call of Duty has an Easy, Normal, Hard or Legend mode), i.e. the game configs might be to hold 7.3%, 8.6%, 10.1%, 11.5% and 12.7%. Of course the game's theoretical hold is not revealed to players. The casinos are allowed to update a game configuration while it is on the floor and idle (not while it is being played). I doubt it has been tested but I believe Gaming Control Board would frown on configuration changes being made to accommodate an individual player, but even if a casino did this, they would not be "giving" a player any winnings, they would just be making it so the player was likely to lose at a slower rate, but still be losing, i.e. dropping from the 11.5% config to the "loosest" 7.3%. This is mostly a moot point anyway, because it is perfectly legal for a casino to offer a player hundreds or thousands of dollars in free slot play (or free bets), that's how they give a specific player "winnings to spend."