Are We Allowed To Ask "Why Not?"

Reuters reports that "White House aides coached President Bush and Vice President Dick Cheney on Tuesday for their appearance before a panel investigating the Sept. 11 attacks that they agreed to under pressure and only if they could appear together and behind closed doors. "

At the administration's request, Thursday's unprecedented questioning of a president and vice president at the White House will not be recorded and a transcript will not be made. Their testimony will not be under oath, either. Why not?