People obey what gets enforced, not what gets announced, and they learn which is which on the second offense.
Repeat a rule with no cost attached and everyone within earshot files it under preference. The traders were camped by the wall because the arithmetic favored camping there, and displeasure does not alter arithmetic. Attaching a consequence they could feel changed what another Sabbath outside those gates was worth, and behavior moved at once, because people move away from pain faster than they move toward anyone else's convictions.
Whoever will not enforce a boundary has not set one. The same runs inward: a standard broken with nothing following becomes the new floor, and a person ends up living at the lowest level they ever let slide.