Maybe he will offer his own place up for these vandals to spray paint his walls?
What do you say Omicron? Let them in your house to express their art?
Wouldn't be able to with the house because of neighborhood zoning, but there's a tool shed out back that could use some work.
The problem there is that it needs paint to re-seal the wood, so I'd have to give it a cover anyway, so I could give it a cover in black - because graphiti renders better against a black background - and then tell the high-school art-teacher to let his students go wild, with the proviso that they're going to get graded, and if it clashes with the motif of all the vines and bushes, I'll selectively spray out the unaesthetic parts, leaving those spots open to be re-done by someone who can do it better.
It's curious that the owner would paint it over if the building's due for demolition anyway. It's implies his lawyer advised him to, because it was a popular sight, such that he might get sued for destruction of public art if he were to just go ahead and demolish the building.