This is actually a really interesting idea, using another image to guide the placement of DBE points. If it's described openly in one's account of the processing workflow, with credit given to the creator of the other image, it seems like an `honest' method to me. It's certainly not `painting'!
It would be interesting to look at surveys of the IFN, made by research astronomers... they might provide a `master database for placing DBE points, maybe? Might make a fun project!
- Marek