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 ....
In that case you have not been paying attention. We have, as the result of the Trial, a clear understanding now of the aspects of the test that did not make sense.
(1) Rossi was trusted by the profs and viewed as an authority on his device
(2) He was in charge of critical aspects of the test, like heating up the dummy
(3) Before the dummy test started to get hot enough to be used as a genuine control he pulled the plug
Had he not been there, doing that, we would most likely have genuine control information which would have made the IR mistake obvious even to Levi.