This has only just occurred to me, but in my mind is a bit of a red flag: The reactor vessel is a sealed metal container, no electrical or magnetic signal of any frequency will penetrate it (It is a faraday cage). And all of the resistive heating elements are positioned around it, so they do nothing but deliver heat to the reactor contents - no special magnetic or electrical excitation can pass through the reactor vessel. All of these configurational details were revealed to the testers by Rossi.
So why did Rossi feel the need to prevent detailed analysis of the input power to these resistors that are no more than resistive heaters? We know he ran it in at least a partially pulsed 35% on 65% off mode with period of about 6 minutes from the thermography. So what possible harm could have come from allowing continuous measurement of voltage drop and current flow through the resistors? As such preventing that measurement serves no sensible purpose that I, or any other engineer/scientist could see, it is a pointless obfuscation. All it achieves is raising suspicion about just what electrical power is really flowing through those resistors.
