Systems, devices, and methods provide for the prevention of laser light escaping a foldable wearable heads-up display (WHUD) when the WHUD is folded. For a WHUD that adopts the form factor of conventional eyeglasses or sunglasses, enabling the WHUD to fold “like glasses” can cause an interruption in the optical path of display light and enable display light to escape into the external environment. This can be hazardous when laser light is used to provide display light. Systems, devices, and methods that automatically detect, sense, and/or respond to the fold configuration state of a WHUD are described. When the WHUD is unfolded a laser-based display operates normally. When the WHUD is folded the laser-based display is disabled to prevent laser light from projecting out of the WHUD through the folded region. Proximity sensors and laser light containing mechanisms also may be employed as alternative or supplementary safety elements.