The web page used an old .NET framework that serialized the application state, base64 encoded it, then dumped it in a hidden form field at the bottom. When you navigate pages, the data is POSTd back to the server to achieve a "stateless" web app on the server side
The reporter had to view source and base64 decode the data
Obviously still trivial but I think the laws are also very ambiguous on "decoding" and "accessing"