Hmm, a little harsh.
" the minute you hit save on the document, it is already outdated" really? So if I had a customer table with columns first name, last name, marking them as PII would be outdated almost immediately? Once there is one row of data in that table, I'm struggling to imagine an example where the metadata will ever be out of date.
If you want to be GDPR compliant then knowing which data is in or out of scope is critical. Especially when considering pseudo sensitive data which isn't as obvious to identify.
@Ronny Smith, if you had a more comprehensive strategy then I think the article would have had a warmer reception. Methods for identifying GDPR data, labelling it, maintaining that metadata. Lastly giving an example of how a customers request to remove their personal data might play out with your extended properties approach. Thanks for the writing the article and getting the community thinking about GDPR concerns.