I agree it's a shame when Wal-Mart opens up a big box store in a community, only to abandon it a few years later when some other community throws tax incentives at it.
But the article at the journaltimes website is enlightening. The roofing nails were allegedly dropped off between 9 and 11 AM. The rally started at 2:30 PM. Thus the ralliers drove over the nails in broad daylight.