My question involves a traffic ticket from the state of: North Carolina

Three days ago my 17 year-old son was issued a citation at a traffic stop. He was issued the citation for being out after curfew. The trooper did give my son the white original but failed to have him sign it. My son's information is there plus information on the incident but there is no signature, either from the officer or my son. Is this a valid citation?

I called the DA's office and only got as far as the secretary who claimed its still binding even without a signature. The DA has yet to return my call. No one has offered to site which law supports the position that an unsigned citation bears any legal weight. Its my understanding that tickets like this have to be signed, either by the officer issuing it or the person its being issued to. I also have a concern that my son's 4th Amendment right was violated by the traffic-stop ( the 4th Amendment provides projection against illegal search of personnel effects and papers).

Any advise on this issue would be greatly appreciated.