  A local gauge symmetry can not possibly be a mere redundancy of the
description, provided that 1. charge is nonzero.
  2. we also consider divergent gauge transformations, whose brackets with
local transformations contain global charge operators.
  If these conditions hold, unitarity requires the existence of gauge
anomalies. We describe the relevant multi-dimensional generalization of affine
Kac-Moody algebras, explain why it only arises if the observer's trajectory is
explicitly introduced, and contrast it to the Mickelsson-Faddeev algebra which
pertains to chiral-fermion type anomalies.
