When you are shipping your car using an auto transport service, it is generally not recommended to pack items or place boxes inside the vehicle. Auto transport companies typically have regulations and restrictions regarding the contents of the vehicles being shipped. Here are a few reasons why it's discouraged:

1. Safety: Adding extra weight from boxes or items can affect the handling and stability of the vehicle during transportation. It may increase the risk of damage to your vehicle or other vehicles on the carrier.

2. Liability: Auto transport companies typically have limited liability coverage for the vehicle itself, not for any personal belongings inside. In case of loss or damage to the items, the transport company may not be held responsible.

3. Insurance coverage: Auto transport insurance typically covers the vehicle, not the contents inside. If your personal belongings get damaged or stolen during transport, they may not be covered by the carrier's insurance policy.

However, if you have a legitimate reason to transport items or boxes in your vehicle, it is best to check with the auto transport company beforehand. Some companies may allow a limited amount of personal items inside the vehicle, as long as they are securely packed and do not exceed a certain weight limit. It's important to communicate and clarify such details with the auto transport company to ensure compliance with their policies and to avoid any potential issues during transportation.