They were selliung lawn signs in Virginia as well.
The article was based on one person's reaction in Minnesota, but I'm sure it's nationwide. I doubt a campaign would allow one (or a few) headquarters to try and make money that way when everyone else isn't.
As I just posted to another, it'll be interesting to see how many Obama signs pop up in our little burg after the convention; in relation to previous elections. This is Northern Illinois, a Democrat state, but we're rural and a Republican area.