Completely off the hook. Otherwise, they'd have no incentive to come on the show.
Yes, travel is definitely included.
Ultimately you're right - if there's a $5000 amount hanging in the balance - that either one side is going to take home, and/or one side is off the hook from losing - the appearance fee shouldn't matter too much. But a lot of people don't look at it that way. Since most of these defendants never plan to pay what they owe in the first place. :)