I am strongly anti capital punishment, but for solid and rational reasons.
Stories like that just weaken the anti case.
https://en.wikipedia.org/wiki/Hanging#Medical_effects
http://www.forensicpathologyonline.com/e-book/asphyxia/hanging

http://www.capitalpunishmentuk.org/Hanging_myths.pdf

http://www.academia.edu/3003781/Post-Mortem_Appearances_in_Hanging_and_the_Cardinal_Sign_in_Ante-Mortem_Hanging_to_Ascertain_Hanging_as_the_Cause_of_Death