Is energy always conserved?

I thought about this a lot. I mean: A LOT.

And this is a neat argument. However, it still did not satisfy my curiosity completely. How are the physics laws changing? If we perform the same experiment, we still see the same result. The time invariance holds. Does it not?

Maybe I missed something subtle Diana said. I'll come back and watch this again in a few days after thinking about it some more.