Why is a barcode called a “proof of purchase” even though it’s there before you purchase it and remains whether you actually purchased the item or not?

Question

Basically, the title. Why is a barcode called a proof of purchase, even though it’s usually printed on the item and is still there even if you have stolen said item?

In: Economics

Answer 1

Its not proof of purchase by itself, usually. But it does prove that you had the original packaging, which likely means you purchased the item new.