Drake equation always bothered me when used in argument of contact probability, because it doesn't take into account time. Yes, there might have been billions of extraterrestrial civilizations, but that doesn't mean there are currently ones that 1) already can communicate or receive EM waves, and 2) not yet deprecated use of EM waves. Oh and there's also speed of light issue.

>What if we decide to invade what seems to be small civilization... What if it's a honeypot?

A plot twist like this would make a movie like "Avatar" very interesting: humans invade a beautiful moon with a seemingly backwards indigenous civilization so they can steal its natural resources, it turns out it's a honeypot (or a protectorate) of some far more advanced civilization, which then decides to wipe out all of humanity. I think this would be a great movie, though there wouldn't be a sequel (at least not one with any humans in it).

If you actually read the trilogy I mentioned, by "elimination" the author doesn't mean an invasion. The advanced races literally manipulates laws of physics to its extreme to remotely wipe out star systems without ever exposing themselves.

The methods range from rudimentary ones like turning the star of a system nova to god like ones like dropping the dimension level of a region of space from 3D to 2D.

Yes, it's a fantastic series of reading :)