  The statistical hadronization model is a simple and efficient
phenomenological framework in which the relative yields for very high energy
heavy ion collisions are essentially determined by a single model
parameter---the chemical freeze-out temperature. Recent measurements of yields
of hadrons and light nuclei covering over 9 orders of magnitudes from the ALICE
collaboration at the LHC were described by the model with remarkable accuracy
with a chemical freeze-out temperature of 156.5 $\pm$ 1.5 MeV. A key physical
question is whether the freeze-out temperature can be understood, literally, as
the temperature at which the various species of an equilibrated gas of hadrons
(including resonances) and nuclei chemically freeze out as the model assumes,
or whether it successfully parametrizes the yield data for a different reason.
The yields of weakly-bound light nuclei---the deuteron and the
hypertriton---provide insights into this issue. The analysis indicates that a
key assumption underlying the model---that hadrons (and nuclei), just prior to
chemical freeze-out temperature, are in thermal equilibrium and are
sufficiently dilute as to have particle distributions accurately described
statistically by a nearly ideal gas of hadrons and nuclei with masses given by
their free space values---appears to be inconsistent with the chemical
freeze-out temperature output by the model, at least for these weakly-bound
nuclei.
