Madam Zhang Xianling knows that every year, at this time, she will get a few "visitors" who will stand guard at her ninth-floor lift landing or at the stairway, or park themselves downstairs and insist on taking her wherever she wants to go.

After 30 years of having such uninvited company, she now just shrugs off this state-sponsored surveillance. At least they are open about keeping watch now, not like the early days of lurking in the shadows and hiding behind walls.