While I agree that you should not just wander around La Boca, Caminito happens to be very safe. I actually work there and nothing has ever happened due to the amount of police presence (Perfectura, to be exact).
Cheng if you do decide to go to Caminito stop by our shop. Its located right in front of the main corner. The exact address is Magallanes 802. We sell mostly sports related items but also carry t-shirts, keychains, etc. Its the first shop on you right as you as you walk in.
Oh and one last thing, everything dies at 6pm so definitely go before that time.