This is another reason why I prefer to buy in-person if possible. I bought a Legacy Skids in-person that had one of its guns loose in the box and could have easily fallen out. I deliberately bought it because it was otherwise a good-looking copy and I just knew that it would fall out and some kid would get that Skids for a present.
I wonder what happens to lost little accessories lying around in a warehouse. I guess either a worker throws them away or tries to put them back where they belong - probably mostly the former. In my mind there's this box in the employee tea room where loose bits are free for all.