The clerk has pointed out to me that any person examined under this part who wilfully gives false evidence is liable to such punishment as may be imposed for perjury. That certainly doesn't answer Mr. Batters' question, but I will say that it's not totally unusual that witnesses are sworn in. I've seen it happen at many committees, and I don't believe there's any point in pursuing this much further, except to direct the clerk to take the necessary action to have it done.
On May 2nd, 2007. See this statement in context.