  We study theoretically the parallel quantum wires of the experiment by
Auslaender et al. [Science 308, 88 (2005)] at low electron density. It is shown
that a Hall effect as observed in two- or three-dimensional electron systems
develops as one of the two wires enters the spin-incoherent regime of small
spin bandwidth. This together with magnetic field dependent tunneling exponents
clearly identifies spin-incoherence in such experiments and it serves to
distinguish it from disorder effects.
