So far it's only been at GameTraders that I've seen them. They could be import items, because as well as local stock GT import a few select items (they often have Japanese blind boxes and prize figures for example) from overseas.Damn lol I was at 2 different GT today, if I had of seen this post I would have checked.
If it helps the same company seems to make a few different doormats as I saw Marvel and DC themed mats with similar tags, but yeah I'll check next time, hopefully in a few days time.