  Toward the goal of extracting the weak angle alpha, the decay B^0/B^0-bar to
a_0^{+/-}pi^{-/+} was recently measured. The decay B^0 to a_0^+pi^- is not only
forbidden in the factorization limit of the tree interaction, but also strongly
suppressed for the penguin interaction if short-distance QCD dominates. This
makes extraction of alpha very difficult from a^{+/-}\pi^{-/+}. We examine the
simlar factorization-suppressed decays, in particular, B^0\to b_1^+pi^-. The
prospect of obtaining alpha is even less promising with b_1^{+/-}pi^{-/+}. To
probe how well the short-distance dominance works, we emphasize importance of
testing helicity conservation in the charmless B decays with spins.
