A whiteboard's writing surface is its most valuable and most vulnerable part, so the whole move comes down to protecting that one flat face from pressure and scratches.
Pro tip: Whiteboard frame corners are the most common damage point; a strip of cardboard folded over each corner and taped is a five-second fix that prevents dents.
Watch out: Never lay heavy boxes flat on top of a whiteboard's writing surface; even moderate pressure can leave permanent marks or dull the erasable coating.