I read somewhere that pickpockets put up these signs on purpose, so you instinctively touch the location whatever the most expensive item you have on your person, so that the pickpocket (who is watching nearby) will know where you are keeping it (i.e. a phone in your pocket, wallet in your coat, etc). So, assuming that is true, maybe keep it in mind if you see one of these.

“Objection, Your Honor. Exhibit C clearly states…”