  CP-violation in $\Delta A_{\textrm {CP}} = -0.154(29)$, in the $D^0 \to
\pi^+\pi^-/K^+K^-$ system, is established and its central value is one order of
magnitude above the naive Standard Model (SM) estimate. It remains unclear
whether this is due to currently incalculable strong interaction matrix
elements or genuine new physics (NP) such as a shift in ${\cal O}_8$ with a
weak phase. We show that the interference of the long-distance (LD) terms with
the ${\cal O}_8$ matrix element can give rise to $A_{\text{CP}}^{D \to V
\gamma} = \textrm{few} \cdot 10^{-3}$ (for reference values
${\textrm{Im}}[C_8^{NP}] \approx 10^{-3}$). In addition, it is pointed out that
the ratio of left- to right-handed (photon polarisation) LD amplitudes is
measurable in time-dependent CP (TDCP) asymmetries. We argue that both theory
and experimental consideration favour weak annihilation (WA) as the dominant LD
contribution. More definite progress could be achieved by either computing the
radiative corrections to WA or the measurement of the charged modes
$D^+_{(d,s)} \to (\rho,K^{*})^+ \gamma$ and $D_s \to \rho^+ \gamma$.
