The rooms are dark and gloomy by design, makes it harder to see the merchandise
In KP the only light comes from the Karaoke TV screen. Think you are right, the approach is largely the same for most of them, although some do try bit harder to make sure you are happy with what you get, or got after the fact. KP is famous for this, its what keeps me going back even though the girls are, relative to what is discussed on this board, a bit old and tired.
Keep on mongering