Ignoring the implausibility of fan/staff reported 'someone senior doing a thing' reports, John Wardley in particular, ask yourself - if you were redesigning a ride, why would you do such a thing?
Lets go with the suggestion that John Wardley is working with Merlin (which we have no concrete evidence of, he's long retired and his more recent contributions have been in an advisory/spokesperson capacity) and he is working on a refresh of Duel (which again is very far from being anything other than a rumour). Why would he be 'riding it with documents and sheets'? He could, presumably, have access to the whole thing if he's working on such a project. He could have the house lights turned on and off to be able to visualise a scene. He could walk the track and if he really needed to he could arrange to have the ride in an emergency stop state, and then take a car, ride a section, call for another emergency stop, walk back and reride over and over.
Or he could just take a ride to refresh himself of the feel of the attraction - which wouldn't need any 'documents' nor 'sheets'.
Doesn't pass the sniff test.