A particularly ugly thing happens if the HN mods for some good or bad reason decide to ban an account: their contributions will be there forever, with no ability to append explanations to previous posts. This will after May 25 be illegal for services offered in the EU, but I kind of think that the same courtesy should apply to non-europeans.
If you contribute to public knowledge/discussion, then taking your ball and going home leaves huge gaps in history, the same way you see [deleted] throughout many Reddit threads.
Is the GDPR that far reaching?