You can't effectively defend hundreds of kilometers of an underwater pipeline, you can only increase monitoring but that doesn't stop the pipe from being blown up. In fact the charges could have already been placed, before any extra monitoring was deployed, and are just waiting for a signal.

The point being - Russia has sent a very clear message that if we don't stop pushing back on Ukraine, that pipeline is next to blow up. There is almost nothing we can do to prevent it if they want to make it happen.

It's not a clear message if they don't actually say, nor even strongly hint, "Stop pushing back on Ukraine or Baltic Pipe is next!"

No. It would make more sense for Russia to quietly blow up Baltic Pipe and say nothing.

I mean, that's not how Russia operates. They poison government critics abroad using a compound only they could possibly have, and then say "it wasn't us". They want everyone to know it was them, without saying it was them explicitly - that's just not what they do. Even if a Russian submarine blows up the Norwegian pipeline tomorrow, with recorded footage of it happening, Russia will still say it wasn't them.

What has Russia gained from any of their actions thus far in the war in Ukraine? I wouldn’t discount something solely because it appears to be a short sighted action that backfires in their face.