Huh? A witness can't be exposed to public testimony???? This judge is taking the fear of "tainting the witness" to an abject extreme.... who appointed this one?
It is a bit of a technicality, because the government lawyers meet with the witnesses and discuss the testimony in advance. But still witnesses on the stand often do not say what is expected, and there are rules to keep them from being "coached." It only seems uneccessary when you aren't the defendant.