On the note of the Q-thruster, you are of course implying that it works by violating known physics principles. The possibility of the design working due to some unknown principle that someone stumbled upon by accident does exist, the realm of possibility is vast though probability is a different matter. On another note, as I have read more into the concept it wouldn't technically violate what we know unless it did actually work as a truly reactionless drive but the concept is believed to function on a theoretical principle involving quantum vacuum virtual particles. However, the concept makes a lot of assumptions without proof they are real in the first place. In the end it wouldn't be the first time someone discovered something other than what they thought they were making by pure accident.