"They all carry signs, do they?"

                They particularly avoid signs, but you can see which ones run when a cop drives by. And, not reading English, sometimes they run from mailmen, UPS drivers, trombone players from the Salvation Army, dog catchers...

                Any if you happen to drive a late model white pickup, you can turn on the emergency flashers and suddenly race off the road into a grape vineyard, and they just simply scatter.