I agree, I was thinking about it while writing it. My thinking was that it should somebody sworn in to try not break the chain of trust. But adding somebody new

I agree, I was thinking about it while writing it. My thinking was that it should somebody sworn in to try not break the chain of trust. But adding somebody new in a chain will always weaken it (in this context). As the sibling comment mentions, it wouldn't have to be mandatory as well. It's just that in general I find the "anonymous sources" a bit too easy to use. It's very easy to have your article say whatever you want by using "anonymous sources".