It will certainly vary by jurisdiction and utility. Though I have no idea if they have ever enforced it, I believe our utility somewhere suggested that operating the system before PTO could be grounds to deny the NEM request (not sure about PTO as well.) I suspect they include the extreme language both to dissuade customers from operating before PTO and to have an option to deal with egregious cases. Probably for most cases, it would just be a warning. I even wonder if that language from Duke is because there is a similar policy but some inspector got too aggressive about trying to enforce it on site rather than just completing the inspection and noting that the system was on.
It helps in our area that the utility doesn't do its own inspections. It does reserve the right to do them but instead just relies on the county inspections. So, once you get county approval, they could only notice an anomaly if they were monitoring the usage data for the account, which they do not seem to do. I would definitely make sure the system is completely off when the county arrived, as I think they would be more likely to make life difficult if they determined it was being operated without their approval.