So this afternoon I completed my second test, and it too was successful
We arrived home just after 3 pm after visiting with my wife's Father (and Mother) for Father's day. After pulling into the garage and chocking the tires I then put the car in neutral using "car wash mode"**. I left the parking brake off, turned off the A/C, turned off the display screen, and set the auto headlights to the "auto off" setting. Then I exited the car with the key fob and locked the doors using the key fob. The car ran all afternoon in this condition until I ended the test at 11:30 pm (elapsed time of 8 hrs, 17 min). Upon ending my test I unlocked the door and as soon as I opened the driver's door the car immediately put itself in park and applied the parking brake.
So for owners who wish to use the car in an emergency to supply power, this is your procedure. In this second test I opted to leave the parking brake off, but in the first test the car operated all night with the parking brake applied. Having tried it both ways, I see no reason to leave it off since the vehicle will immediately apply the parking brake when I return to the car and open the door. Leaving the brake on avoids having to chock the wheels.
For my purpose the car would be strapped to the tow dolly all night to supply 12V DC power to the motorhome, so I assumed that I could leave the parking brake off since the next morning It would need it to be off to continue my trip. Since it re-engages anyway, I'll just have to remember to release it before I hit the road again. (And, of course, disconnect the 12V battery again so that it does not re-apply the parking brake as it's being towed).
**For those who don't read the manual...Car wash mode is engaged when the operator shifts to neutral WHILE
the driver's door is open. This is an important step, since the book says if left unattended in neutral the vehicle will automatically shift to park. Once it's in park, the vehicle counts down an hour if the key fob is removed from the vehicle or two hours if the key fob is left in the vehicle, and then automatically powers down. So to keep the power on, the key is to keep it in neutral in car wash mode.+++++CAUTION+++++
Any Bolt owners who intend to use this procedure for auxiliary power should monitor their power consumption to ensure that the Lithium ion HV pack is never fully depleted. A full depletion could cause serious damage to the HV pack. Any safeguards that GM may have written into their software regarding this type of use is unknown and untested. It is likely that the vehicle would power itself down, as it does if you are driving the vehicle and it reaches a SOC level which the designers consider to be below the operating threshold. But it is possible that all safeguards have been defeated by using neutral and car wash mode. I personally plan to monitor the power consumption in such a way that would never allow the battery to be depleted anywhere near an extremely low SOC and would personally cease this type of operation long before the HV pack reached an unhealthy SOC. As such I have no plans to test what would happen if the vehicle reached an extremely low SOC% using this operation. If anyone wants to risk further testing feel free to share your findings.