The poor mans double die was actually die deterioration doubling, and yes, is very common. Just like die breaks, and clashes. They were trying to ride the coattails of the legitimate 1955 DDO, and succeeding in duping many people. You still see sellers on Ebay and places hyping the poor man's double die, and attempting to dupe people.
So...time to resurrect this thread, if only for a moment. Went to the Dupo Coin Club show today in Collinsville, IL. It was kind of a slower show; I believe quite a few dealers were still returning from FUN. Dealers who were present were, for the most part, very friendly and ready to make deals to a reasonable buyer. Ended up actually leaving with more money than I arrived with (overheard a dealer I've known for quite a while asking someone about buying some silver certificates, told him I had a huge pile at home, and he offered to buy them all.) Essentially traded my silver certs for a big pile of US Mint Sets (most from the Ike years.) Was able to add another 1970 Mint Set and 1973 D Souvenir Set to my hoard, but my best "cherrypick" of the day was this 1956 "Double Bar 5" Washington Quarter (which is what makes it relevant to this thread.) I've found a few of these from time to time (one seems to pop up every couple of months, but always in very circulated condition.) First one I've found that was BU, so it's going in the keeper pile. Let's see if anyone is still watching this thread