A quick answer: Hiding a key outside or relying solely on a dog sign or similar non-tangible measures is not a physical security measure. Physical security refers to tangible barriers and devices designed to block or deter intrusion (e.g., locks, deadbolts, security cameras, motion sensors, reinforced doors, fences, gates). Non-physical or digital strategies (like passwords, two-factor authentication, or monitoring via apps) support security but do not physically block access. If you’d like, I can give a concise list of common physical security measures for homes and highlight examples to avoid confusion between physical and non-physical approaches.