I just ran two non-approved batteries through their use in one of those battery grips. They went in and registered fine without any objection from the camera. The battery icon appeared as usual, or as it would have. I had installed the previous patch earlier so it did at one time show the plug icon.
After the power wore down, the battery icon reflected the drop in power and eventually turned red on the last bar. The camera then locked up from taking pictures or going in to live view.
I then removed both batteries, not replacing either, but rather emptying the battery bay to get a fresh start.
I then installed two more non-Nikon approved batteries and witnessed the green LED turn on briefly, indicating that some sort of function remained of the battery check.
The camera powered on without any objection or difference in functionality.