Of course, if you go to a supermarket with self-service tills you can just put through as many as you like without anyone challenging you or noticing. I was behind a woman recently who bought six packets of 12 paracetamol in three separate transactions, all cash. She'd put two through the scanner, pay the cash, two more, pay the cash, two more and pay the cash. She was in her 40s or 50s, noticed me watching and said "Don't worry, my doctor normally gets the chemist to give me a large box, but sometimes I run out on a Sunday".