So in an anarcho-capitalistic society what do you do if ...
You are with a couple of people and one guy says he'll give you something if you do something, you do the thing and come back for his end of the contract.
He refuses and won't hold up his end what do you do?
Ever been to the lending subforum here on bitcointalk? There are many "verbal" agreements to loan money that end up with someone skipping out.
What is done then?
And how many people are willing to accept a verbal agreement with a user with only 10 posts asking to borrow 1000 BTC?