As I already said, I have some reservations about the fact that witnesses who have been called upon to appear be allowed to leave before the end of the hearing. I would not want this to become common practice. The committee has never accepted that someone be allowed to appear before the committee and then leave whenever they please or when the chair determines that they are allowed to leave. I do not know what the motives are, and thus I do not necessarily want to spend too much time on this issue, but nevertheless, in practice, it is up to the committee to make decisions about the duration of hearings.
On October 19th, 2010. See this statement in context.