Tiles 1 and 3 are slightly elongated, and they tend to turn when you hold the edge. Holding the edge is tempting and practical but really, due to your weight, you will turn the tile. Of course we tried to tighten it already. Many times too. But I think that no matter how we tighten it, the tile will still turn due to the nature of the tile.
Toot, why not screw in a screw to prevent the rotational motion?
It will damage the wall.
Then, why not change the tile?
You change lo.
Screw ni. Why not you change the tile yourself?
I think the tiles are placed nicely enough to warrant my inaction.
So how now brown cow moo?
Hold the center of the tile la, near the screw hole there.
If you turned the tile when you are doing ARC, or when you stepped the tile, or when you are doing a route, please turn it back. Thank you.
Actually, this may help you to be ready for natural climbing. Many rocks can be loose on the natural wall and it is a common misconception among gym rats that all tiles are solidly solid for your convenient yanking (read: the route stimulates natural climbing zomg!).
Again, on the other hand, this may just be another case of normalizing deviance where people are accepting that tiles in the gym can be loose now.