This was before the latest patch but the Golden Key cheat also allowed a player to play the Moxxi slots for free. Also it seems to disable the Moxxi tip jar. You can still put money in but it doesn't seem to count. Reverts back properly if the cheat is disabled.
Don't know if this will still work with the next trainer though.
it didnt notify you and didn't take money and took longer than normal, but spamming it enough would still get you her gun (even though it's sort of pointless with free golden chests).