The “Sai Kung Barrier” is a term used by Hong Kong hikers to describe a recurring disorientation phenomenon reported along sections of the MacLehose Trail, particularly near Stage 1 and the High Island Reservoir East Dam. Local accounts commonly describe sudden loss of direction, abnormal silence, dizziness and an overwhelming urge to turn back despite clear paths and GPS navigation, with these experiences widely discussed in Hong Kong hiking and night-trekking forums.