A survivalist singularity?

Should survivalists declare a "safe haven" and start migrating towards that general location?

I realize that its not a feasible proposition for most people. But does it make sense on some level that like-minded people should come together to increase their chances of surviving, possibly even thriving?

I see definate utility in being surrounded by people who can take care of themselves while simultaneously contributing to the survival of those around them. I am also troubled by the idea that when stuff finally does hit the fan I could be surrounded by people who are utterly helpless and thus pose a liability, or worse, even a threat.

What different ways can we use to identify each other in public so that we can begin to build necessary local networks before things start to go awry?

Christians slap a fish on their car to identify each other, atheists use a fish with legs-- should we have something similar?