  We consider a thought experiment in which an energetic massless string probes
a "stringhole" (a heavy string lying on the correspondence curve between
strings and black holes) at large enough impact parameter for the regime to be
under theoretical control. The corresponding, explicitly unitary, $S$-matrix
turns out to be perturbatively sensitive to the microstate of the stringhole:
in particular, at leading order in $l_s/b$, it depends on a projection of the
stringhole's Lorentz-contracted quadrupole moment. The string-black hole
correspondence is therefore violated if one assumes quantum hair to be
exponentially suppressed as a function of black-hole entropy. Implications for
the information paradox are briefly discussed.
