Harmony will be hard to find if we ignore the rules

The sign seemed clear enough; it pictured a cart with a big red X through it. If for some reason this wasn't understandable, the bold red letters that said "No Vendors" should have been sufficient to erase all doubts. But there, just to the left of the sign sat a vendor selling trinkets from a dirty blanket.
As I passed, he glanced up and flashed a toothless smile. It didn't bother me that he was there; after all, such vendors are an everyday sight in Beijing. As I exited the station, a policeman stood there talking on his cell phone. I stopped for a while to see if he would take any action against the vendor. After a few minutes, the policeman walked off and the vendor continued to hawk wares under the sign that damned him.
Is it just me or do others seem to quietly disobey every rule that is supposed to relate to them? What drives them to do this? No littering, they litter; no smoking, they smoke; no parking, they park. Is the English translation of these signs wrong? Are they really just a suggestion?