..is that they will soon either provide extraordinary evidence or they are a fraud (and therefore an obvious short selling opportunity).
There is absolutely no upside whatsoever to pussyfooting around on their claims at this point. When they go public, they want their stock price as high as possible. With a high stock price they can get the necessary power and influence they will need to compete with other public companies. If they just use half measures and weak demos, by going public they will likely just attract attention and deep pocketed competition that will believe it can do better than them (especially if they see people investing in Defkalion). Their best strategy is to go out very very hard and in a way that makes them the defacto standard and discourages competition or at least gives them ammunition (via a very high stock price) to attack competitors. The way to do this is to provide a public test protocol that suspends all disbelief. Right now, given that Luca (the only known physics PHd with a track record in the bunch) has suspended biz in Italy due to inconsistencies on the testing, I'm betting incompetence / fraud, but I think a really good test by Defkalion with indie observers (especially a videotaped one) will turn that around significantly. Hopefully in the test they will allow the indie observers to open up various parts (especially the pumps, the reactor, the electrical, etc) as well to show nothing crazy.