Insurance, in an "outside the box" anarchic society???? Wow, you really do live inside the box, if you think that it is impossible to have insurance without government.
No, it is you that are out of touch with the "Anarchic society definition. Financial institutions (and like it or not an insurance company is a financial instituion) are the bane of the anarchic society. Soooo... it stand to reason that they would be desolved in a true anarchic society.
Semper Reality