It looks like someone either moved the armor all over the place, or this vest was used as a back drop for a dart board!! There's a huge amount of holes in that fabric that shouldn't be there !!! I would think that if someone was concerned about the fabric having a problem, a small amount of fabric glue (or some other glue) could be applied on the back side, around the pin penetrations with a tooth pick to reinforce the fibers.
If they werent locking clutch backs, that makes sense. They come off so easily. I have to take pins off my uniform every time it goes to the dry cleaner. I've been using the same holes in the fabric with locking clutch backs for over ten years! I don't foresee having this problem with my vest.