The problem with the choking issue, at least in Los Angeles is I think due to the law enforcement. My memory may be a bit weak here, but as far as I can remember, a story told by Royce Gracie, Royce used to teach RNC to the LAPD officers, most of the officers did not grasp the idea of technique and blood choke aspect of the move and kept on putting the blade of their forearm in front of people's necks crushing their trachea. After some hospital bills and lots of complaints from the public, LAPD is banned from using choke holds as an arrest procedure. The law against choke holds may have been passed or because of that incident.