iPhone and Entune: Can I get rid of the cost warning dialog?

Just switched from Android to iPhone, and doing the requisite rejiggering to get the head unit and phone cooperating again. But I've been unable to get rid of the "Connect [name of phone] for Internet?" cost warning dialog each time I connect the phone to the USB cable. On my Android phones I was able to disable it by going into each phone's Bluetooth settings and unchecking the "Show cost warning" checkbox. I've done this for my iPhone too, but it doesn't seem to work. I assume that's because, unlike Android, the iPhone doesn't actually connect to Internet over Bluetooth; it uses the USB cable. (My car has the Display Audio with Navigation and Entune. If I understand correctly, the higher end audio systems can stream Internet over Bluetooth to both iPhone and Android, but for some reason the system I have can only stream Internet over Bluetooth to Android phones.)

So I'm left wondering - is there some way to stop that dialog from coming up all the time? Sometimes it doesn't come up if I don't access a screen involving the Internet apps. But I do like to use those apps, so I'm having to deal with that dialog with annoying frequency.

Phone: iPhone 6, iOS 10.2
Car: 2014 Prius III (Display Audio w/Nav and Entune)