I agree with you and I've seen it happening already at the Christmas markets in Hamburg, Germany. I bought a hot drink that came in a ceramic mug (which require

I agree with you and I've seen it happening already at the Christmas markets in Hamburg, Germany. I bought a hot drink that came in a ceramic mug (which required a deposit) that I then returned after walking around the rest of the market. I'm sure some people kept them as souvenirs but it seemed like the vast majority were returned.