To decry wind energy, saying we're slowing the rotation of the earth down or something.
Actually we ARE doing that with tidal power stations. It's basic physics really, that energy we gain from tidal power has to come from somewhere. Just like when we use Jupiter to slingshot our space probes, we're actually changing ITS orbit as well. But it's nowhere near the scale to actually have a measurable effect, so I'm not really advocating that we shut them down.