Did China have a good reason to not ban international travel during the COVID-19 lockdown when it banned travel to and out Wuhan inside of China? I hear sensationalized news reports claim that China didn't ban international air travel to spread the virus to other countries (I doubt it since a lot of them just spread lies without doing any proper research), but were there legal and political reasons why China didn't or couldn't ban international travel out of and into China?
... is inscribed in most major human rights instruments and is intended to ensure that people can move freely, including out of the country they are in, without unjustified obstacles. States are permitted to place restrictions on the right to leave but any such restrictions must be necessary and are subject to a proportionality test.
Let's not forget that around January 23, many people (including yours truly) weren't taking Covid-19 seriously. I leave it to your imagination to see what could've happened if China had banned international travel then.
In international law, disease control allows nations to take quite drastic steps restricting the travel of citizens and foreigners.
In most parts of the world there is a (more or less open) debate about the economic and humanitarian costs of the lockdown vs. the humanitarian and economic costs of the virus. Leaders who order a lockdown are villified by those who either refuse to believe the science or rationally fear that the cure is worse than the disease.
This gets even more complicated because the deadliness of the virus was unknown. It is still not exactly known even if we know more now. If China hard closed their borders back then, that would have disrupted international commerce and also the lives of countless foreign citizens. Based on the information in December or January, a lockdown was not justified. Look at the earlier SARS outbreak.
Consider the reports when Peru closed their borders and foreign tourists got stranded.
This question is probably not answerable as asked for now. While some details of the Chinese decision process have been made public, those regarding where to ban travel from/to have not, as far as I know.
On the other hand, we know how long it took the US to ban all travel from China [except repatriations]--until Jan 31... and that there was significant infighting inside the US administration on the matter during those nine days (after China announced their Wuhan lockdown). Other countries acted within a similar time frame, e.g. there news on the same day (Jan 31) that Italy was banning all flights from China. (If one were to nitpick, the Italian ban went into effect a couple of days before the US one, which became effective Feb 2.) Furthermore, even CDC officials now admit that the US was probably too late in banning travel from Europe (mid March.) It probably wasn't any easier for China to decide what to do precisely in terms of travel bans.
Also of some interest are post-hoc studies on the effect of the travel bans, although there was probably no precedent on this scale to guide decisions back in late January.
First, Wuhan Tianhe Airport was closed on Jan. 26th, so no international flight can leave Wuhan. Six civil airports in Hubei temporarily suspended on the Jan 26th., Civil aviation prevention and control measures upgraded
The reason maybe is no country will receive them. Who will?
Also, if a patient went to other country, what will Chinese goverment think? What will goverment of that country do?
And many foreigner stay at Wuhan. Some of them are voluteers, some of them can't back at all. Except for being returned to their country by charter flight.