What I had in mind is that China's territory is rather large and they could place a launch site deep within its territory. Flow of information is tightly controlled as it is with the Great Firewall of China in place, and the communist Big Brother having eyes and ears at every corner of its territory, leaving West in the cold without direct means of establishing their mission's purpose, if China chose to keep it secret.
At least any information that could be gathered via intelligence agencies of the West would likely not leak to the public (or so they would try), to avoid diplomatic repercussions. So my question actually is, how likely would any information about China's secret space missions find its way to the general public? To keep this question from being primarily opinion based, I would like you to provide examples of past missions that were launched under wraps. Who disclosed what information and when (how long after the launch) it became public knowledge? How reliable have these past reports proved to be? Are there any instances of faked reports or additional counterespionage measures to throw the West off course?
Could we infer, via remote sensing or other means of tracking the Chinese territory launch site's activity and actual rocket launches, what they're up to? E.g., could we establish what orbit would some Chinese military satellite assume, or its purpose?
Or, if the purpose of the mission was something else than orbiting a remote sensing satellite, do we have the means to analyze potential threat such missions could pose if China chose to keep it a secret?