http://www.swacargo.com/swacargo/acc...rAccount.shtml
The Transportation Security Administration (TSA) requires that Southwest Airlines may only accept cargo weighing 16 ounces or more from Known Shippers or TSA-approved Indirect Air Carriers. In order to ship cargo with Southwest Airlines, you must become a Known Shipper by completing the account application process.
Once your application is approved, we will contact you to set up an inspection of your residence or business. There will be a minimum, non-refundable $50 fee for the inspection. (This fee is mileage-based and may be higher). Once your account is created, we will provide you with a Southwest Airlines Cargo Account or Shipper ID number. You will need to present this number when tendering your shipment to us.
Note: The TSA requires a seven day waiting period from the date of the application before the first shipment may be tendered on a new account.