Have you ever known a government worker to care about anything?
What pisses me off is they have enough money to put cameras up everywhere to keep tabs on the public, red light cameras, etc,etc. but nothing for monuments such as this.
Friggin bastards.
Re cameras at the Wall:
I think the perp considered the possibility of cameras and so sprayed the oil at wrist/thigh level as he walked past. Nothing would be noticed by a surveillance camera until later when the oil had soaked in and discolored the concrete.