2 types;

1/ As a client you can buy insurance, for instance 24/7 support when something is wrong

2/ As a Geekangel, you can get insured for the potential mistakes you make / eg. bricking a brand new iphone :) Geekangel insurance status is displayed publicly, so client know for how much the Geekangels is insured. In this way you can choose a Geekangel to work on your server, knowing that if he fucks up, the insurance will bail him out.