Yes, folding knives can be used to cut hard cardboard. However, it is important to choose a folding knife with a sturdy and sharp blade suitable for cutting through tough materials. Folding knives with a robust locking mechanism and a durable blade, such as those made from stainless steel or high carbon steel, are recommended for cutting through hard cardboard. Additionally, it is crucial to use caution and proper technique while cutting to ensure safety and prevent accidents.