It is definitely still possible to receive class 0 sms, because I believe that is what you are getting in the US when you get an amber alert or other emergency

It is definitely still possible to receive class 0 sms, because I believe that is what you are getting in the US when you get an amber alert or other emergency warning. As far as I can tell, all US carriers restrict the sending of these to just themselves (or official gov sent through them). Otherwise you can imagine the abuse potential.