Yes - I think that’s significant here. It’s unlikely permission was granted to anyone for the One Tree Hill graffiti and an excuse of ‘someone had already tagged it first’ wouldn’t mount any legal defense. It seems foolish to be breaking the law and advertising the fact so overtly, though I doubt it will come to anything.
Also note that much of the other street art is done with permission from the owner, including the faux railway sign murals on Network Rail owned walls. Without pointing fingers, I’m sure some of those artists did start less legally though have ‘come good’ - personal tastes aside.
Anyway, I know it’s good to be strong and have positive self-belief, but I think it’s also good to be humble and honest with one’s self at times too.
I’d be a lot more impressed if Harkiran was able to say ‘I got it wrong, sorry’ and then perhaps even go back and paint it all dark green or something. That would be a real show of self-strength in my opinion.