In the coming age of wearable computing, devices such as Google Glass will become as ubiquitous as smartphones. Their foreseeable deployment in public spaces will cause distinct implications on the privacy of people recorded by these devices. Particularly the discreet recording capabilities of such devices pose new challenges to consensual image disclosure. Therefore, new Privacy Enhancing Technologies (PETs) will be needed to help preserve our digital privacy. At the time of writing, no such PETs are available on the market to communicate privacy preferences towards Glass. In the scientific literature, a handful of approaches has been presented. However, none of them has been evaluated regarding their affordances and overall usefulness. In this paper, we provide the first systematization and qualitative evaluation of state of the art PETs that were designed to communicate privacy preferences towards (wearable) cameras, such as Google Glass. The purpose of this paper is to foster a broader discourse on how such technology should be designed in order to be fully privacy preserving and usable.