My question involves landlord-tenant law in the State of: California

My landlord wants to move in a exchange student that is a minor (age 15). We will be sharing a bathroom. If for any reason the owner is not around, and the minor gets into some type of accident/trouble or causes one - am I liable for not intervening? Should I have the owner write an addendum to my lease that clearly states that I am not responsible; not have any guardianship over this youth when they are away? I have clearly stated to them (the landlord) that I do not want, and will not accept any responsibility over this person.