I think another possibility worthy of serious consideration given the implication of the presentation I linked above is the existance of many bracewell probes[1] in our solar system.
If an alien civilization has the capability of seeding the universe with spacecraft it's definitely not a stretch that they would burrow them inside an asteroid to conduct subtle observations of noteworthy planets.
Well, since we can never know that for sure (even if we identify a filter, is it the filter? Is there more than one?), the best we can do is try to move forward and make it increasingly unlikely that the things we think are candidates to being a filter can effect us. First and foremost, get off-planet, which brings us full circle to Musk, who is on record as stating he started SpaceX to spur Mars colonization.
Either because it tends to involve the development of Von Neumann probes that unexpectedly turn on their creators or because it signals to latent berserker probes sitting in the asteroid belt that we have reached a threat threshold and need to be eliminated.
Either way I agree that we need to try to get off this planet in a meaningful and permanent way.
