It's impossible to predict which paintings will last and which won't. In New Orleans I painted on a dilapidated shop in a street littered with abandoned cars and rotting mattresses, then two hours later the piece was gone. It turned out I'd picked the side of a crack house and the proprietor didn't like the attention.
My lawyer's opinion is that the cops might not actually be able to charge me with criminal damage any more - because theoretically my graffiti actually increases the value of property rather than decreasing it. That's his theory, but then my lawyer also believes wearing novelty cartoon ties is a good look.
The human race is the most stupid and unfair kind of race. A lot of the runners don't even get decent sneakers or clean drinking water. Some runners are born with a massive head start, every possible help along the way and still the referees seem to be on their side. It's not surprising a lot of people have given up compeating altogether and gone to sit in the grandstand, eat junk and shout abuse. What the human race needs is a lot more streakers.
Remember crime against property is not real crime. People look at an oil painting and admire the use of brushstrokes to convey meaning. People look at a graffiti painting and admire the use of a drainpipe to gain access.