Wouldn't owning one address always make you own the other address as well?
ie: If I have address A as my BTC address, and address B as my BCC address, if someone incorrectly sends BCC to A, then I can import the privkey of A into my BCC client and refund it the BCC anyways.
Of course you are correct, and I feel a bit stupid.
I started the thread after reading about a seller who had his payment sent to the wrong address, and the general opinion seemed to be that he had lost the money, or the buyer had. In fact, that might have been the problem on reflection, it was the buyer who was posting ( not on Bitcoin talk btw).