1. It sounds like to me that there is no room for human compassion in crypto-anarchy. (Seems like we will all end up sitting in our "compounds" armed to the teeth and if anybody comes along we either blow'em to bits or pay them anonymous digital cash to go away).
Crypto-anarchy is in fact not really anarchy, since it only addresses some kinds of authority, ie government, and only in certain situations. True anarchy involves the dissolution of other hierarchical relationships, including those that spring from private property. Get rid of private property and many of these problems disappear.
How does crypto-anarchy/libertarian/anarchy propose to deal with the "tragedy of the commons" where by doing what is best for each persons own interests they end up screwing it up for everyone (Overgrazing land with to many cattle is the example I've been given). The "prisoner's dilemma" is another example.
I believe that the standard argument is "Eliminate the commons." (by auctioning off to the highest bidder perhaps)