Perhaps I should clarify how I am encoding the video for DVD. I'm using TMPGE, which has a setting for the frame rate of the incoming video as:
"23.976 (internally 29.97)"
That tells TMPGE that although the video file format is labelled as 29.97, the actual frames in the video look correct if played at 23.976. I also tell it to set the pulldown flag. It then takes all that into account and produces an MPEG2 file that looks correct when played on a DVD player.
This is why I don't want the frame rate settings in the video altered if it can be avoided.
If I were really being picky, the frames look correct if played at 24fps. But since I haven't had any problem with audio drift, I've just let TMPGE do its thing as described above.