Sounds believable that countries do these alerts for sometimes political reasons, but China is actually keeping people from leaving the country for unspecified reasons and is seizing people, even their own citizens.
I'm not saying it's OK, but it's hardly a reason to warn people not to go there.
China has been holding 3 Canadian's, likely in retaliation to the CFO of Huawei being held. So it may seem warranted here?
This is another bullet point in an escalation trend we've been seeing between the West and China, mostly surrounding infrastructure and political pressure/flurries of arrests and high profile detainments, in both regions.