> he fact that he spent hours trying to patiently explain the science behind it when first arrested suggests that either he started to believe his own story or was really, really confident in his ability to lie to others.

Or he knew that what he was going to be charged with was fraud, which requires intentional deception. Therefore failing to keep up the lie would be exactly the same as pleading guilty.

If this guy can convincingly maintain the lie that he personally believes they work, then he has plausible deniability.