Unless he allows independent testing of his "coolant", I'm not convinced it isn't a chemical reaction.
Another fact is that Rossi's patent protection is weak to non-existent.
His credibility too.
Like it or not, the above scenario fits more of the publicly avialable data than any other.
Complete fraud is still more likely.
No possible chemical reaction can provide the level of energy measured. Despite all the hoopla to the contrary, the measurements were NOT either badly done or inaccurate. In this area I am a genuine expert. The supposed "errors" are all bullshit.
"His credibility too."
Which is why the observations of the different attendees are important evidence. It isn't just Rossi.
"Complete fraud is still more likely."
Based on the totality of available data, no.
You are, of course, free to believe whatever you like, as I am, despite the self-appointed posting police.