Sundials in public parks and schools are often victims of vandalism. The most common problem is the gnomon (pointer) being broken off or stolen. Amazing though that such a simple piece of brass can cause so much trouble to correct. Many public sundials are one of a kind designs and often of early 20th century vintage. A simple replacement is not available at Home Depot. if a new gnomon is found or custom manufactured, then there is the task of how to not only afix it to the dial face (which may be a difficult to maneuver piece of carved stone) but how to do so in a way that prevents future vandalism.
The story linked below from the Hawke's Bay newspaper details the troubles of one such public dial in Napier, New Zealand. In a short 3 years, the parks department has had to replace two brass gnomons on a beaitiful marble art deco sundial at Napier's Marine Parade.
After Sundial Was Vandalized
(photo Glenn Taylor)