Yes, absolutely. Any package that is not fully encased in corrugated cardboard, including but not limited to metal, wood, hard plastic or soft plastic (e.g., shrink wrap) may incur an Additional Handling fee. ShipNerd has no way of knowing how customers package their products, so this fee (if applicable) will be charged as a shipping adjustment if the courier imposes it on the shipment.
Irregular Packaging?
If you're shipping an oddly-shaped item such as a tire, a wooden pallet, or a guitar (items that you're unable to fit in a standard rectangular box), couriers consider these types of items irregular packages, and can impose an "Additional Handling" fee 😬.