Symbios in the AVS Forum sent a eMail to Francie Bauer @ Dish Network and simply asked her, "Will the DTVPal use PSIP, or Gemstar's TVGuide solution"? She said she'd have to ask the Engineers in London. Today she got back and said the DTVPal uses a PSIP guide.
Not only that but it has "DTV Program" as some listings.
It would be nice if the "Downloading Guide" screen was a setup screen and you don't have to keep repeating this, I do agree that this sounds like it is getting all the PSIP data for you.
You are correct that to receive PSIP data you have to tune to the channel so I have no idea how it operates if you don't run the "Downloading Guide".