I too have questions about derived information.
My first ever judge call was when I was playing PE, the runner hit a Snare early on when there were 3 servers, and later wanted to run again, but wanted me to tell him where the Snare was. I declined to reveal which server had the Snare, or share my recollection of what servers he had run previously. Judge was called, and backed my interpretation of the rules; that I did not have to reveal any face-down card or remember and share which servers the runner had run and when.
The runner ran and hit a different Snare, which he again declined to trash (the runner was worried about Jackson Howard recycling the Snares back into R&D), but now marked the server with a piece of paper. This time I called the judge to ask if marking the server in this way counted as note-taking, which would not be allowed. Again, the judge agreed with my interpretation, and the marker was not allowed.
My question is: was this interpretation correct at the time? is it still correct now under this new ‘Derived Information’ rule?
How should we interpret the ‘Derived Information’ rule? At first reading, it always seems to run against most other ANR rulings I have seen on hidden information, and I am genuinely confused by it.