Like the thieves who wrap a cheap greeting card around a more expensive one, and then go to the self check out. Crooks dream up a million ways to scam the system.
RFID tags will all but eliminate that.
Some installed already in the U.S.A. Few, at the moment.
IBM RFID commercial - from 2007
https://www.youtube.com/watch?v=eob532iEpqk