Why are the total energies of transition states so commonly corrected for zero-point vibrational energy? So often I see total energies of transition states corrected for zero-point vibrational energy which always confuses me.  Zero point energy is the lowest energy that a ground state minimum energy configuration can have at 0K in a vacuum.  Transition states are indeed not minima, can never be isolated, have one imaginary mode of vibration, etc.

So why do people constantly factor in zero-point vibrational energy to the total energy for a transition state?  Obviously this is done to have 'comparable' minima and TS energetics (if you are applying ZPE to the minima) but is this even physical?  If zero-point correcting the TS, should the zero-point energy of the imaginary mode be included in the summation or excluded (or should both quantities be provided)?
At the transition state, you have exactly one vibration mode with imaginary frequency (which corresponds locally to the reaction coordinate), and $3N-1$ other “normal” vibration modes. In the transition state theory, you separate out the reaction coordinate (consider it infinitely slow compared to the other movements). Thus, when you consider the energy of the transition state, you have to include the contributions of ground state energy of all the other vibration modes.

The more rigorous way of looking at it is to use statistical physics, and to consider the partition function of the transition state. See here or there for such treatments.