If the board had registered users, it may also need to maintain a database which easily can be hacked by someone from China. This would put all critical comments and reports about crap "schools" in China at risk with unknown consequences for the security of Westerners working and living in China

That is a perfectly valid point. The westerners need to be protected. And given the propensity of netizens to "human flesh search" someone who posted something online in said country due to their culture not respecting individualism or personal privacy and space, I would also be wary of such a system.