Using Christmas lights as an example, when a human being is looking at a beautifully decorated building draped in Christmas lights, their pupils will constrict (since more light is shining into the eye) which makes it hard to see or focus on the surrounding area.
That said, if people cannot see a criminal, they cannot react. So, more lights do not always mean more visibility.
Additionally, when watching top horror and thriller films, there is one thing that most of the directors use to their advantage — shadows! No matter where light is placed, if there is an object between the light and the ground, there will be a shadow. Now pair an actual shadow with decreased visibility thanks to constricted pupils, and there is definitely an opportunity for danger to arise.