They are fucking weird.
Speaking as someone who used to consider himself a LOLbertarian, AnCaps kind of happen in two ways:
1) When LOLbertarian/Propertarian ideology is sufficiently challenged, but the Propertarian in question doesn't have much political or economic education beyond Von Mises, Rothbard, and Rand. Thus they get more extreme about property rights (except intellectual property for some reason), rather than going the other way.
2) When young, (usually) white, Americans decide they're "anarchists" but don't really know what an anarchist is. Thus due to a fundamental misunderstanding as to what the State actually IS (due in large part to the "more vs. less government" propaganda they were raised with) they end up supporting the State while taking an extreme stance against government as an institution. This explains why they keep trying to be accepted by their "Fellow Anarchists" (AnComs) and get really annoyed when they're told they aren't anarchists.
The AnCaps that I've encountered tend to be very sheltered and more than a little socially awkward. They're usually male (though I have encountered self-identified female AnCaps) and usually give off that "Homeschooled" vibe.
Relevant:
http://communities.washingtontimes.c...ing-anarchist/ <-- Becoming an AnCap, from an AnCap's point of view
https://www.facebook.com/pages/Shit-...23379661136741
AnCaps at Occupy:
http://www.youtube.com/watch?v=lpPoGkwx6OE
*Note: I have no idea who that kid is - I'm guessing he showed up for a day or two very early on and then left. The guy interviewing him, Adam Kokesh is a self-described "Anarcho-Capitalist" radio host, in the vein of Alex Jones. He's most famous for calling for an armed and loaded "Open Carry March" on Washington DC, that never happened, because he got arrested at the Global Marijuana March a week or so before, and that was enough to scare him off from trying something so blatantly illegal.
AnCaps were not common at Occupy, even early on - when younger tea partiers were still showing up with their "don't tread on me" flags.
SO think Homeschooled kid, or deadman-esque paranoid redneck, or tech guy (For some reasons programmers seem to gravitate towards the label as well.)