“In short, the implication that there is a safe way for law enforcement to restrain using carotid manipulation, or traumatic manipulation of cerebral blood flow in any form, is simply false. Carotid compression contributes to potential neurologic sequelae via oxygen deprivation, embolic risk from mechanical vessel wall trauma, or arrhythmia. The possibility of devastating repercussions is too high to merit the use of neck restraints in any circumstance."