If you could actually achieve essentially unlimited energy at very little cost you wouldn't tell anyone and would just connect it to the grid and collect your money. There is no reason to "prove" cheap cold fusion.
I'm not going to make any claims as to whether or not this is a scam, but your logic is completely wrong. Most people would probably need investors to finance any mass production. To get investors, you (normally) have to prove that it works...
With cold fusion the claim as always been that it would be small scale, cheap and would easily scale up. You don't need mass production when you can generate unlimited energy for free. The only reason you would need investment would be for the original device (which is required to prove it works anyway), it would then pay for the next set of devices, etc until you owned the earth. If you can't break even quickly on a 1MW generator that doesn't cost anything to run, your device is too expensive to be practical since you are generating about $1m of electricity a year.
