If someone made a GIGposter for my band, didn't distribute it, never intended to, yet sold it, even for a buck, I'd be a little peeved. But only a little. He should keep his stack of posters and cut his losses. If it's okay to sell them then tomorrow morning I'm going to make a really cool poster for uh...the White Stripes' next show and sell it. While I'm at it, I'll throw together a Turbonegro poster. And I agree. this poster leaves a lot to be desired, even for the outsider, naive, primitive art look.
However, if he had originally intended to distribute it as an actuall promotional poster, but couldn't, didn't, whatever - that's a little better. But perhaps not if it was never commissioned by the band or venue.