I will not comment on the art v. vandalism issue. I did, though, learn a new word when reading the NYCTA Official posting of dont's on the subway system. Like no spitting, etc. One rule was no graffiti and no scratchiti. Lexan or similar is prone to scratch marks being etched into it with knives or screwdrivers.
...scratchiti... That's what happens to my plastic window inserts when I take them out to paint a car......... Ed
