As of 2 years ago (pre-COVID), no. You needed a passport, and that's it. I doubt things have changed materially since then.
Some people require permission to leave (e.g. certain party members/SOE managers/etc), and I'm sure a lot of others are on government watchlists and will be stopped at the airport.
But it's patently absurd to take that and infer that every single overseas Chinese student was only allowed to leave if they spy/sabotage the West.
You would not have been approved for a passport, if deemed unworthy.
Whilst other countries do this, in the West, denial to issue a passport is typically predicated upon conviction of extremely serious crimes. Not merely because some hidden agency does not like your social standing.
Further you require a valid passport, or an 'exit permit', to exit China. You may not leave legally without one.
Not so in the West. You can not be detained from leaving the country, at all, passport or not. Other countries may refuse you entry, but this is not remotely the same thing.
For example, if I as a Canadian attempt to fly to the US, Canada grants the US CBP the right to setup pre-clearance facilities in Canadian airports. And often airlines handle this for foreign powers as well. However, that is a foreign power denying me entry, not my government denying me the right to exit.
As an example, I can just walk across the border to the US, and have broken not a single Canadian law. US law, if I do not report to CBP, yes.
Meanwhile, one would be breaking China's laws to cross the border from China without a passport, or exit VISA.
I did not indicate your worth, or lack of worth, to the Chinese state.
Instead, I stated that people are not granted exit VISAs, or passports, if not deemed worthy of one. It seems as if you are attempting to twist my words a bit here.
