Citations, as promised (from my vet tech friend):

Quotes are from Reptile Medicine and Surgery, D. Mader, second edition, 2006

For reference the 2000 American Veterinary Medical Association Panel on Euthanasia was a panel formed of the foremost experts on reptile medicine and euthanasia in the country. If we can’t trust them, who do you trust?

Chapter 33

“The 2000 American Veterinary Medical Association (AVMA) Panel on Euthanasia has published several guidelines for euthanasia of reptiles”

“Rapid freezing, such as dipping in liquid nitrogen, is approved and effective in animals less than 40 grams. Larger species may not be rendered unconscious rapidly enough to prevent discomfort.”

“Reports have state that placement of a reptile in a conventional freezer is a viable technique for euthanasia (Frye, 1984). Cooper, Ewebank, and Rosenberg (1984) contest that the animals may experience pain as ice crystals form within the tissues and the skin. The AVMA Panel on Euthanasia does not consider this an acceptable or humane method for euthanasia, even if prior cooling is performed.”

American Veterinary Medical Association: 2000 Report of the AVMA panel on Euthanasia, Journal of the Veterinary Medical Association 218(5):669-696, 2001.

Frye FL: Eutahnasia, necropsy techniques and comparative histology of reptiles. In Hoff GL, Frye FL, Jacobson ER, editiors: Diseases of amphibians and reptiles, New York, 1984 Plenum Press.

Cooper JE, Ewebank R, Platt E., et al. Euthanasia of amphibians and reptiles, Potters Bar, England, 1989, Universities Federation for Animal Welfare.
It is against the law for vets to use freezing (other than liquid nitrogen as mentioned above) as a method for euthanasia.

Someone said this has been discussed before, and I don't mean for the thread to get too far off topic, but it was brought up.