Réponse :
A mon avis c'est Banksy mais tu ne dois sans doute pas en avoir besoin.
Pour la description tu peux sans doute le faire (homme en noire, entouré de tags, etc. ).
Pour la deuxième partie, plusieurs choses :
- As a famous artist, he may want to keep his normal way of living. He can live like us.
- He creates a myth, he become the man with no face. The only proof that he is him is his art.
- He can travel anonymously, talk to specialists without prejudices.