This is what I'm talking about - the neutrinos were detected twenty six years after observation of breaking of mass-energy conservation law. That means, over one quarter of century the physicists were forced to live with violation of one of most important principles of contemporary physics - such a situation can emerge anytime later. I also noted it just a few posts before. Do you think, you're smart, if you're allowing me to repeat it?
Actually this situation (the violation of mass-energy conservation law) did already happen before twenty six years already for example in form of reaction-less drives like the Shawyer's EMDrive or Woodward's Mach Drive. These devices move forward despite they don't release anything back - in this sense we also observe the violation of mass-energy conservation principle. Not accidentally every reaction-less drive is also potential perpetuum mobile (why?). Now the physics should also wait for a new neutrino-like particle, the reactive force of which would explain this anomaly.
But we didn't observe it - actually the physicists even didn't start to look for it. So why the mass-energy conservation law should be preserved in general?
There is no deeper reason for it - only leaky experience.