I was there visiting today and one black guy came to me. He put a blue rope around my wrist and declared it is a sign of friendship. Then he asked for money, I said I do not have any. So two more black people approached and it was pretty scary. I insisted I do not have paper bills and only have coins, so they demanded all the coins in my pocket and I got away with giving them 6 euros. It ruined my day so bad.
Be careful when you visit Sforza Castle in Milan. It seems that there is no administration or any police force, plus a lot of people from Africa and Middle East there hanging around. The castle itself is impressive. But it is not worth the risk of being pickpocketed or robbed.