They do, it's on the purchase page and on your email itinerary...I know this as I had the same issue with another airline so I always look for this before I buy tickets.
This is what is written on the rules and restirctions of my flight when i booked in August '08, its the second to last paragraph...its not in blinking lights but it is there.
This ticket is non-refundable and non-transferable. Name changes are not allowed after purchase. Upgrade charges and premium seat charges are inclusive of applicable taxes and fees. Fares and availability are not guaranteed until purchase. Please note that security regulations may require us to provide government agencies access to data you disclose to us.
If you need to adjust your schedule, you can make changes and cancellations via our website.
Flight and/or date changes from Main Cabin to Main Cabin will incur an additional change fee per person of $75.00 for tickets booked on or after June 6, 2008 and $40.00 for tickets purchased prior to June 6, 2008 and any applicable fare difference will be credited or collected.
Flight and/or date changes from Main Cabin to First Class will incur no change fee, but any applicable fare difference will be collected.
Flight and/or date changes from First Class to First Class will incur no change fee, and any applicable fare difference will be credited or collected.
Flight and/or date changes from First Class to Main Cabin will incur no change fee, but any applicable fare difference will be credited.
You may modify your schedule until departure time. Again, our Help section never takes a day off, so please don't hesitate to use it for answers to all your questions.
*Special Request Fees include additional services that were requested, such as: premium seat upgrade, additional baggage, unaccompanied minors, pets, etc. For applicable fees please see our FAQs or Contract of Carriage.