You're thankfully mistaken on this.
R57 Scope of Panel’s Review, Hearing
The Panel has full power to review the facts and the law. It may issue a new decision which replaces the decision challenged or annul the decision and refer the case back to the previous instance. The President of the Panel may request communication of the file of the federation, association or sports-related body, whose decision is the subject of the appeal. Upon transfer of the CAS file to the Panel, the President of the Panel shall issue directions in connection with the hearing for the examination of the parties, the witnesses and the experts, as well as for the oral arguments.
After consulting the parties, the Panel may, if it deems itself to be sufficiently well informed, decide not to hold a hearing. At the hearing, the proceedings take place in camera, unless the parties agree otherwise. At the request of a physical person who is party to the proceedings, a public hearing should be held if the matter is of a disciplinary nature. Such request may however be denied in the interest of morals, public order, national security, where the interests of minors or the protection of the private life of the parties so require, where publicity would prejudice the interests of justice, where the proceedings are exclusively related to questions of law or where a hearing held in first instance was already public.
The Panel has discretion to exclude evidence presented by the parties if it was available to them or could reasonably have been discovered by them before the challenged decision was rendered. Articles R44.2 and R44.3 shall also apply.
If any of the parties, or any of its witnesses, having been duly summoned, fails to appear, the Panel may nevertheless proceed with the hearing and render an award.