Except in those hearings in which the child’s behavior is not at issue, the child and a parent should be present at the commencement of hearings. If the child’s behavior is not at issue, the hearing may, in the court’s discretion, begin without the child’s presence. If a continuance for the purpose of securing the attendance of a party or for any other reason is advisable to ensure a fair hearing, it should be granted. If for some reason found valid by the court no parent can be present, the court may appoint a guardian ad litem prior to the hearing.