"Smells Like a Hoax, But . . . "

This comment from ECW reader ‘Fabio’ was posted on an older thread, but I thought it was worth posting here for people to respond to. I think he raises a good question, and one that could be typical of people just being introduced to the topic.

Hi all, I’m a scientist in an unrelated field to physics, and I’ve been casually reading about Rossi’s E-Cat for the past hour or so. I must say that I’m very skeptical and I agree with those that say that this shows all the signs of a hoax. There is one thing though that bothers me, and maybe some of you can answer my question or give me pointers to forums where my question has been discussed:

If Rossi is hoaxer, then surely his competitors (I’ve heard about Defkalion and Brillouin) are hoaxers too, right? In particular Defkalion is a direct spin-off of Rossi’s ideas… so as a logical consequence of the hoax theory, someone in Defkalion must know about the trick behind the e-cat and must be repeating it in its own demonstrations. And what about Brillouin? https://www.e-catworld.com/2013/09/whats-the-google-brillouin-connec…

If it is a hoax, how come that the trick is spreading from company to company without being exposed by the (many!) who are interested in this?