Why didn Claudia and Madeleine use their dresses to hide from the sun?
Unless specifically designed to block light, fabric is normally light-permeable. Even if they had been able to shade themselves from the sun, any one of the vampires or their mortal slaves could have checked on Claudia and Madeleine to be sure that they were dead. If they were hiding under their dresses, the fabric could have simply been moved aside at that time to kill them or their clothing could have been removed.
