Chaffing and winnowing is presented as a form of confidentiality without using encryption. This is beneficial for countries where encryption is regulated. 

Below is a diagram from [Wikipedia](https://en.wikipedia.org/wiki/Chaffing_and_winnowing) showing Alice sending "1001" to Bob.

[![Chaffing and winnowing](https://i.stack.imgur.com/FQofz.png)](https://i.stack.imgur.com/FQofz.png)

My question is what is the purpose of Charles in this picture? Why can't Alice just chaff the data herself before sending it directly to Bob?

Additionally, if this assumes that traditional encryption methods aren't available, how are Alice and Charles talking over a secure channel?