Just a clarification......this is just a preliminary interrogation process, in which both sides are questioned in order to determine whether a case should be filed or not. Sharifs chose not to attend, which means, that NAB will file a case unilaterally, without any due objections from Sharifs. No arrests are due just because Sharifs did not appear.
Now once the case goes to court, then the court may determine if Sharifs need to appear or not. And if they dont appear upon the courts calling, only then arrest warrants are issued.