  The anomalous excess of small-kT photons radiated along with multi-hadron
production, is challenging the physics community over four decades, but no
solution has been proposed so far. We argue that the problem is rooted in the
comparison with an incorrect model, usually called bremsstrahlung model. It is
believed to be an extension of the Low theorem from the 2 -> 2+gamma process to
radiative multi-particle production 2 -> n+gamma, where either initial, or
final charged hadrons participate in radiation. We demonstrate that this breaks
down unitarity of the S-matrix, so contradicts the optical theorem.
