I was really surprised the first time someone asked — I think it was in a review of a proposal — about whether it was ethical to do citizen science. “Isn’t this exploitation?” was how the concern was phrased. Getting unpaid people to do what was previously paid work might seem problematic. As citizen science has grown, so too has thoughtful criticism of the practice.
The term ‘citizen science’ covers such a wide range of activities that I think it’s hard to address the ‘ethics of citizen science’ broadly. As citizen science is broad, so too are its ethics, covering everything from completely ethical to unethical.
Source: Is citizen science ethical?