"M. R. D. Foot argues that blackouts did not impair navigation by bombers because navigators focused more on reflective bodies of water, railroad tracks, or large highways.[13]"

This is about as close as you will get to the truth.

You also have what is now called Visual Flight Rules https://youtu.be/0BP_H5tzIM0?t=22

which backs up the claim that pilots used waterbodies to navigate. When people found out, many filled them automatically just like some people knocked out street lights. There own paranoia was used against them, just like we see with migrants in hotels today, or paedophiles in the neighbourhood.