Totally, I'd feel different about it too if it were intentional, but what I'm saying is always bet on human stupidity first.
Though to note chinese factories and stuff are awful at keeping up to security standards, I am a mechatronic and the company I work for is sometimes sent out to China ( from Germany) and I have seen stuff man.. it would be also no surprise if they disabled failsafe programms intentionally there.
Though this time you are probably right, someone fucked something up.