atomicindy, that is correct. I have found that the airline reservation departments are a bit in the dark on this, and really give suspect information. Barb Kater (Barb's Belize) posted a little ditty a few weeks back that showed how to read your taxing authorities and the amounts as posted on your voucher. However, it was a bit complicated for this old Wolverine educated Hoosier boy and I threw in the towel.
All I know is that in March '04 we paid it in cash at departure (USAIR), in June '04 I had 17 tickets and it was paid on all those tickets (USAIR), in November we had six couples (a mix of AA and USAIR) and it was included in those tickets with both airlines. It is now $35 since, I believe, the first of June '04.
It is my understanding that the servicing airlines had finally made the arrangements with the Belizean authorities to collect the departure tax in the ticket cost and remit to the BZ government much like they do in most destinations that have such taxes.