To ensure that the thief's future suppliers would continue to leave their product attached to the pole?
I suspect removing safety signs may be seen more gravely than theft of personal property. Putting the sign back means you committed one crime rather than two.
Yeah for real, the city might actually try to do something about someone removing signs. Not even joking.
In my experience, they don’t. But it was just a street-name indicating sign that was removed to make way for a sidewalk cut, tossed aside and never re-mounted. Eventually some scrapper took it I bet.