What is it with bags

What's this latest trend of having the word "bag" printed on the side of bags? I saw someone walking around yesterday with a little brown bag that had "little brown bag" printed on it. Is that in case we're not actually sure if it really is a little brown bag or not?

I've actually got a "Big Green Bag" from Tesco, which is big, a bag and, ironically, mostly blue. (By the way, if you've got a motorbike with luggage on it, the Tesco Big Green Blueish Bag is great as an inner pannier).

You don't see cars driving around with the word "car" stamped on them, or people with "human" tattooed on their foreheads, so why do we need the word "bag" on bags?

Rant over.