There are plenty of discs with empty AUDIO_TS folders. That doesn't make them DVD-As. Unless there's data in there, it's just a regular old DVD-V. The "DVD Audio" logo has been tossed about rather carelessly by labels in recent times.
Yes, it's true that not every disc with an AUDIO_TS file is a DVDA....but every DVDA has an AUDIO_TS file, which is not true of every DVD-V (they are rare on modern DVD-Vs in my experience). Which was my point in writing 'like a DVD-A'. And in accord with the DVD-Audio labelling on the product itself.