I've been on the receiving end of a few shady product requests - popup ads, url hijacking, spyware. Even though the ethical questions involved were not that hug

I've been on the receiving end of a few shady product requests - popup ads, url hijacking, spyware. Even though the ethical questions involved were not that huge, it was always difficult to come through unscathed and it cost me a fair bit of sanity and work relationships. I can only imagine the burden when it actually involves human life or wellbeing, and am thankful to have had the luxury of choice. This gets me to wonder if having a universally agreed code of conduct (like the one from ACM mentioned somewhere else in this thread), and the backing of some kind of union could make a difference - at least developers would have some comfort that they wouldn't be fired for raising ethical issues, or even refusing to do work, without the company having to face legal action. What's the equivalent for other lines of work?