That scene had a full moon as a plot point. It's pretty easy to see around you in a sparse forest on a moonlit night. The only real issue is how quickly your ey

That scene had a full moon as a plot point. It's pretty easy to see around you in a sparse forest on a moonlit night. The only real issue is how quickly your eyes can adjust to darkness (e.g. they fire off spells and patronus charms that should be ruining their night vision).