Probyn, I believe spray cans were used and not canned paint. Wizard, correct me if I'm wrong, but the pictures that Wizard took look like Krylon spray paint to me.
I agree that notifying the authorities is essential. Wizard did notify Ranger Brad Burns, and I hope he is working in conjunction with DCV on coming up with a method to remove that graffiti as soon as possible.
At Blacks Beach , graffiti has been minimal due to the virtually impossibility of spraying or painting crumbling sandstone cliffs. I think the same is true of San Onofre as well.