[terrabytes]

Suppose that data in quantities orders of magnitude greater than that used in this project was scraped from the internet and used to train a model that powers a commercial product.

Is it ethical to sell something that is dependent upon data that people might consider sensitive? Even if they willingly lent their photos to fitness organizations, it's unlikely that they would have predicted that AI would make use of their personal data in the ways it does today.

[rayheberer]

I'll be honest, this sort of thing didn't cross my mind when I was gathering my small dataset. To me, if someone had willingly let an organization publish their photo on the internet, it was free game.

That said, having considered what you've pointed out about people's expectations when having their data taken not accounting for things like deep learning, I would be hesitant adopting the same attitude if I were working on a product or paid service. Right now I can't lay down a bottom line as to whether I think what you described is ethical, but I do think that the general public should be more informed when it comes to how their data, even old data, could be potentially used.