This is the second doc in the past couple of years discussing Banksy and also a worthy contributor to those who are distant from, yet interested in, his drawings. As an alternative school teacher I sometimes would take ss on graffiti wall art tours (and/or Rocky Horror showings) so I have a little appreciation. And, to be up front, not all wall tags are positive contributors to a wall. Many are just self- aggrandizement and show little respect toward the people who own that wall or passers viewing their scribblings. It's another double edged sword issue.
Should those drawings be saved; sold or erased? Well, the answer is in one's personal definition of art. Some view art like everything else in life - temporary and at some point will no longer exist - so why bother! Others say the role of art (or all human endeavours) is to see if we can improve toward some idealized state of being/mind/behaviour thus art (or anything that helps in that journey) should be saved & promoted. Does Neanderthal wall art help us when we happen upon it in a cave and ponder what it tells us about humanity tens-of- thousands of years ago?
What Banksy did with the Palestinian wall drawings may help ease Palestinian, by analogy, ever decreasingly sized Indian reservation style imprisonment. Only time
What Brian Grief is trying to do in putting one up for public tour is no different than a thousands-of-years old Egyptian or Chinese sculpture on tour to peoples around the world that offers first-hand experience of an event well beyond anything they are likely to ever experience. Or that fossil of a dinosaur in transition to bird (Archaeopteryx) being viewed in person. As is often said - let time be that judge. There's truth in art, established over time. But, can time get it wrong?