The best way to convince a jury that your system works is to prove it in public before the trial begins. Delaying proof of performance just improves the case for the defence.
Every time Rossi made a public test, there always been someone who considered that test was not accurate enough, someone who thought the test could have been done in a better way.
If you want to prepare a proper test, you have to choose carefully every detail, especially if you are disclosing to the world a new and revolutionary kind of object. How could you do everything in the right way if you are spending most of your time with an attorney?
Now Rossi is trying to win a battle, and I think he can't do it in the best way if he has to organize the QuarkX launch. His choice is the best one.