If it is an accused then probably the police have greater responsibility to advise the accused of their 5th Amendment rights. In the event of a witness, it is not so clear. As I know the history of this question, I still don't know. On the one hand, if a party calls a witness they should inform their witness of their rights (not that we do this in a civil trial, but perhaps we should). On the other hand, if the DA is looking for a Perry Mason moment for which he can charge another person with a crime, then I think the DA would have an obligation just as the police would have in an interrogation. But the judge is there to uphold the law and see that things are done according to the Constitution of the State (and US) and in compliance with appropriate procedure. Perhaps the judge should have instructed the DA to speak with the witness regarding her rights during a recess or something. Perhaps we should ask Laura Dykes to get her take on it. :) I'm sure it would be educational and probably pretty entertaining as well.