One piece of warning: The owner's manual may not always be right.
We are at the peak of Snowbird season down here in the southwest, and I have already towed in two different 2018 Chevy SUVs that were being flat-towed within the same week. The issue is with the instructions: flat-tow by placing in neutral and turn ignition off.
You can't turn the push-button ignition off in neutral, only park. So you either run the engine in neutral all day long, or start it every couple hours and run for a while to charge the battery. Another option would be to disconnect the battery once in neutral.
Yes, GM is aware of the issue by now. I am not sure how they will handle it, whether a re-programming of the computer in cars that people desire to flat-tow, or a prohibition in the manual.
I'm sure this will be a growing issue with the proliferation of push-button ignitions.