  Let S be a smooth affine algebraic curve, and let S' be the Riemann surface
obtained by removing a point from S. We provide evidence for the congruence
subgroup property of the mapping class group Mod(S') by showing that its
congruence kernel lies in the centralizer of every braid in Mod(S'). As a
corollary, we obtain a new proof of Asada's theorem that the congruence
subgroup property holds in genus one. We also obtain simple-connectivity of
Boggi's procongruence curve complex for curves with at least two punctures, as
well as a new proof of Matsumoto's theorem that the congruence kernel depends
only on the genus in the affine case.
