then permissive drivers are always covered (well at least on my policy).... as you would be covered by your ins. if you wrecked your friends car.... it's basically the same. You friend doesn't have you on their insurence, but your ins. will cover you in their car....That situation is kinda different, but check the permissive drive option... see if you have it....most likel y you do... but it wil only cover damages up to 10,000.... If not then your sis's insur. will cover it if she has the min. liability.