If you decide you need additional value protection after your trip has been booked you can add coverage up to $3500 per bag. To add value protection, simply log into your account:
My Account > Trips > View Trip > Edit > Coverage
The value protection applies to each shipping label, and you can increase the value up to the point you ship your luggage without needing to print new labels. Once your luggage has been shipped you can not change the value protection.