In the past month or so I've noticed several 'yard sales' that are more like ongoing businesses rather than an individual or family disposing of excess clutter. One house in my neighborhood is regularly selling several new mattress sets plus a half dozen or so treadmills among other items- enough to literally fill the entire front yard not just once or twice but at least once per week. At day's end the seller packs a large delivery truck with the unsold items and drives off to parts unknown.
The house in question may not even be occupied but merely used due to its location on 43rd Ave.
Just this afternoon I drove past a similar yard sale with numerous washers and dryers on display, again on 43rd Ave. between Bethany Home and Missouri. It's bad enough (and illegal) when people sell cars by parking them along major roadways; these yard sales aren't really any different although I don't know if Phoenix has any regulations in place to stop this blight.