  In this Letter, we study black hole area quantization in the context of
gravitational wave physics. It was recently argued that black hole area
quantization could be a mechanism to produce so-called echoes as well as
characteristic absorption lines in gravitational wave observations of merging
black holes. One can match the spontaneous decay of these quantum black holes
to Hawking radiation calculations. Using some assumptions, one can then
estimate the natural widths of these states. As can be seen from a classical
paper by Bekenstein and Mukhanov, the ratio between width and spacing of
nonspinning black hole states approaches a small constant, which seems to
confirm the claim. However, we find that, including the effect of black hole
spin, the natural widths increase. To properly address any claim about
astrophysical black holes, one should examine the spinning case, as real black
holes spin. Thus, the word spinning is key to the question of whether or not
black holes should have an observable spectrum in nature. Our results suggest
that it should be possible to distinguish between any scenarios for which the
answer to this question is yes. However, for all of the commonly discussed
scenarios, our answer is almost certainly no.
