As a frequent passenger on red eye flights across many carriers, you start to pick up on trends on airlines. On all of the red eyes I have taken before and after the merger with US Airways, it seems as in the coach cabin that they prefer to keep the lights on throughout the flight.
While some airlines may turn on a few lights during the beverage service, American seems to keep all of their lights on, and only in the economy cabin. In Business class, they do not keep the lights on.
As a data point, Delta always turns off the lights during their red eyes. In fact, I can think of a single red eye on Delta where they turned the lights on for the beverage service, and many people around me quickly complained and asked what they were doing. The flight attendants claimed they needed the lights on to see as they did the beverage service. This type of experience on Delta however is not the norm.
In the days of pre merger US Airways, Flight attendants would often turn on the lights during red eyes, 2-3x time hawk credit card offers, with little regard to the passengers sleeping. Personally, I prefer Delta for red eyes, given they have the most respect for passengers sleep.
What is your experience with domestic red eyes?