Just found this out today, real simple. I know there is an RDX cargo light we can swap, but this requires no new parts or spending money, and is real simple.

First open your hatch. Look at the hatch lock, should see a white plastic piece.



Hold down the handle that opens your hatch, and move the white plastic piece counter clockwise. Should look like the picture below when done.



As you can see, cargo light is now switched off.



Go in reverse to reset everything, as you can't close the hatch with that white piece of plastic in the off position.

Hope this helps fellow FitFreaks out that like to keep their hatch open for tailgate parties...etc. Can someone confirm if the GE8 mechanism is the same?

 

I don't have a GE but in my GD this works just fine, just make sure you remember to move it back into position! You can imagine slamming the hatch shut with nowhere for the latch to go could very well break something.