Yes, the instrument cluster lights are always on when the vehicle is on in an S. L and LE only turn on the instrument cluster lights when the parking lights are on.
They could be self illuminating esp when you go under a shade, underpass, tunnel, etc. Even with your headlights off and with just the day time running lights on it glows in dark places automatically is what I noticed.
They aren't glow in the dark or turned on in just dark areas. They're lit by LED and always on the second the vehicle is on, no matter what position the headlight stalk is at.
It's because the S has the multi-information display and it requires being lit in order to be visible (like the screen of a cell phone or any other LCD-rgb display), so the rest of the instrument cluster is lit along with it.
My '08 Matrix was the same ... mainly because the cluster lens was tinted from the factory and you couldn't see anything with the car off unless the sun was hitting it directly.