Two things:
- Auto-spam when the app sees 5+ of the same message from the same account, with the same tags in a short period of time (classic spam).
- "Show Anyway" button, that asks for confirmation to view when 5+ of the people you follow REPORTED (not only blocked) someone or a note. For reported people, the reports last for a day, for individual notes it lasts forever. If you follow the reported person, messages appear as normal.
The code is open source. Anyone can see for themselves.