ooooooh, I have to disagree 100%!!! You were correct in saying the show is for the general public.
Sure, while the general public won't see most of the MINUTE details in your set with the lights down, you still have to detail your sets for OTHER reasons.
I tell our people all the time, I want to be impressed with the lights on or the lights off! Larry said it best; you don't do it for the customers as much as the media. When you invite the news crews and other haunters into your event with the lights on, it should be detailed enough to peak interest and look GREAT in photos and vids!! If I had gone to the Darkness last week and seen nothing but black walls with little areas of decorated sets, I would've been PISSED!! We start working on our event, like most, at the end of the previous season. That gives us 365 days to do whatever we need to take care of. I guess I don't have the super-ability to IMAGINE where my prop pieces are going, therefore, I need to do lighting last. I figure you set it up the way you WANT it then light the scene accordingly. That method has apparently worked with AMAZING results for many haunters in the industry.
I feel like you have to know when to go into extreme detail and when you can cut a corner or two. If you truly planned out all the elements in your head prior, you'd know, "hey this hallway is gonna be dark, let's not put this extremely detailed prop in this hallway cause I really want the customers to see it."
I could go on forever, but I digress.
...and with that, there are my .02 cents!!