One mold can be reused and the light, empty shells can be shipped easily around the country and filled with sand on site. (much like they do with water or sand filled highway barriers)
The more the rioters destroy them, the more they multiply.
Actually, I rather like that idea.
Perhaps we can start making molds of hated figures (which is most everyone) and pop them up everywhere around the country.
Mocking, taunting them.