We lived in an apartment complex that had small rocks as the mulch for the landscaping. So, basically, the entire landscaped areas were litter boxes for the cats in the neighborhood. We had to drag them out to the street to keep them away from all the "kitty treats".

One afternoon, we came home and one of the kids snuck by us and was roaming the common area for several minutes before we realized he was out. Ate a bunch of gravel along with the treats. For the next couple of days, everything he ate came right back up within a few minutes.

Vet said the gravel plugged him up something awful. Had to have surgery to scrape out the gravel so he didn’t die of sepsis.

So, yeah, it’s a thing.