It's not something you'd notice when it was happening. After all it's nothing out of the ordinary, a cat on your lap, rubbing up against you. It's only several hours later that you realise, once again, that part of your clothing is missing, this time the tag on your sweater zip, silently swallowed, gone, if not forever, certainly to all intents and purposes in any usable form.
Little buggers. Just as well I don't tend to wear jewellery.