Sounds like the gym manager needs lessons from one of my local gym owners. He started with the usual "Please rerack your weights after use".
This was followed by a notice that read "Look here! I am sick and tired of picking up your plates. If you can't be bothered to put them back, I'm going to scatter them all over the floor and you can go and look for them".
This lead to some reracking in a random order, so we got to see "For fuck's sake. You put the plates on the peg which is labelled with that weight. GOT IT ?".
Then followed a couple of notes with an arrows pointing to an incorrectly racked plate, saying "Another fucking moron who can't read !".