Kinematic Inevitability and Geometric Non-Fixation of the Weak-Field Factor Two

In metric theories of gravity admitting a Newtonian limit, the numerical factor two in the weak-field expansion of the temporal metric component is often interpreted as fixing the Schwarzschild horizon radius to r_h = 2GM / c^2. We show that this inference is logically unwarranted. The factor two arises kinematically from the geodesic equation and constrains only the relation between the Newtonian potential and test-particle motion. It does not determine the non-perturbative horizon condition unless an additional mass-identification postulate is imposed. We formulate the C2 framework, in which the kinematic (Newtonian) mass and the geometric mass defining the horizon are structurally decoupled, leading to a strict gravitational radius r_h = GM / c^2. We demonstrate that Solar-System constraints are satisfied via standard screening mechanisms acting exclusively in the weak-field sector. The resulting construction is minimal, covariant, and observationally admissible, while exposing a hidden structural assumption underlying the standard Schwarzschild radius.