I wouldn't be surprised if even the limited monitoring Asus is doing is pushing the limits of what Nvidia find acceptable.Sure, they can't do anything fancy with the voltages but I find it hard to believe the firmware can't drop the power limit to protect itself if it detects an imbalance. Or shut the card down.
It could be they only got away with it because they're Asus as by monitoring it, and highlighting an issue, they're alluding to it being a problem.