Proposition: Collision contacts cannot alter a separated germ

Let $C$ be a closed collision locus and let $O$ be an open set disjoint from $C$. If $\mathrm{supp}c\subset C$, then $c{|}_O=0$. Consequently adding $c$ cannot change a distributional germ on $O$.

Proof. Every test supported in $O$ is supported away from $\mathrm{supp}c$ and therefore pairs to zero with $c$.