Do you leave lights on for your dog if you go out at night?

My family has always left lights on for our dogs, when we go out. I'm not sure if we do it so they won't feel lonesome or if it's because it seems more natural to leave them on. Regardless, we always have left at least one lamp one, for our four pups. Which seems like enough, I would say. I'm sure they wouldn't mind the dark, but it would seem almost wrong to leave them without it, now!