From the beginning of the first comment in the HN discussion you link to: he explained that it was only supposed to fire if the shooter was wearing a special w

From the beginning of the first comment in the HN discussion you link to: he explained that it was only supposed to fire if the shooter was wearing a special wristband with a little radio frequency transmitter inside. The CEO put on the wristband and went to pull the trigger. ... And it didn't shoot. Just silence. An "oops" which is entirely unacceptable for any law enforcement/self defense use case.