This assumes all of the vast majority of engineers are easily replaceable. Given that several tech companies prefer the chance of not hiring a good fit over the

This assumes all of the vast majority of engineers are easily replaceable. Given that several tech companies prefer the chance of not hiring a good fit over the chance of needing to fire someone, I think the cost to a company if a significant subset of its engineers declined unethical work (especially engineers who at this point are high enough to have a good idea of the broad scope of the software) would make it difficult to perform what you suggest.