If Rossi was lightly involved, and seldom present, then the report would be more respected, than if Rossi was there all, or most of the time, as the documents show was the case.
I don't understand why Rossi's presence at the Lugano test has to disturb you so much. In the report, is it written that Rossi conducted the test? The actions he has made are listed and are perfectly understandable since the Professors were not required to know how to load or turn on an object they saw for the first time. If you believe in the authors' word, you know that they had the control of the test. If you do not believe it then you would have suspicions even if the documents did not report Rossi's presence. But it is difficult to understand why professors with a career and a reputation should lie about a test they chose to do and describe. Really absurd ....