CAGS only looks at TPS, RPM, coolant temp, maybe a few other parameters, and then energizes the blocking solenoid to block 2nd and 3rd gears.
I'm not sure if the PCM knows what gear it's in, but even if it did, tapping into that data would be difficult or impossible.
An installer explained to me that they physically install a laser sensor in the shifter area to confirm neutral. That's why it's so expensive...
I've debated spending the money many times.
Of course, if we install it ourselves, we just leave mr. sensor out. But, that could turn into a nightmare...idk