This "potential" pending event is so big, that there is no way that such a secret can be kept much longer if in fact it turns out to be true after all.

Trouble is, by the time we learn all about this through normal channels, you and most others will be out of time to properly prepare. Gathering food for long term storage and building supplies will be next to impossible to acquire easily, do to the onset of global pandemonium, hording of food, and the introduction of international martial law that would follow.  That is... if Nibiru is real after all.

Building materials, let alone heavy construction equipment will be next to impossible to obtain.

The old methods of survival will not work in this case, as there are elements to this "possible" coming global change that you must factor in when looking to find the right shelter. Factors that will be to late to adjust for, should things start to go down hill from an x-class solar storm.