I don't think a code of ethics would stop this behavior, at least if derived from the existing rules governing PE societies. The relevant ethical rule that for

I don't think a code of ethics would stop this behavior, at least if derived from the existing rules governing PE societies. The relevant ethical rule that for the (US) National society of Professional Engineering is "Engineers shall hold paramount the safety, health, and welfare of the public." As much as I despise the great firewall and the associated surveillance state, reasonable people can conclude that such measures are in fact in support of "safety, health, and welfare of the public." Ethics in this area are not as concrete as say physical construction, where punishments for a flawed building design or implementation date at least to the code of Hammurabi and seems fairly consistent across cultures. Norms and ethics around surveillance and the role of the state are far less universal. An ethics review board from mainland China could come the conclusion that not creating or implementing these features would be unethical. I do think that engineers should do exactly as you recommend, but I also doubt that our shared sense of ethics are universal enough to get the outcomes we want.