The channel capacity of a binary symmetric channel is
$$ C = 1 + p \log p + (1-p) \log (1-p), $$
Where $p$ is the probability of error in transmission between Alice and Bob.
I have noticed that the capacity is $1$ when $p=1$. It is easy to see why this is the case from the above equation but I don't understand physically why this is the case. If there was 100% error on the channel, surely everything Bob receives is completely wrong and therefore the capacity to send messages is zero. Is it because if we had 100% error on the channel, Bob receives an inverted message w.r.t. Alice's and therefore it still contains all the information? All 0's became 1's and vice versa, so all Bob has to do is flip them all to return the original message, much like sending the negative instead of the photo?
Thanks