[speedplane]

Getting a prototype working would take a week for a skilled machine learning engineer, assuming they had access to well labeled tagged data.

What will be difficult is to push the accuracy up to get actionable information from it. Assuming you're an evil repressive regime, even if you're system had 90% accuracy, you'd be falsely accusing a huge number of people and doubt even a repressive homophobic regime would implement it. Getting that 90% accuracy to 99.9% or higher would take a huge effort, this study isn't anywhere close.

That said, the concerns are real. Automatically sorting hetero from homosexual people, Jews from Christians, or even black from white comes with a tone of moral issues.

[peteretep]

Getting buy-in from an evil repressive regime will be hard if we assume they have a population distribution like anyone else which means a sizeable proportion of those in power are gay but not openly.

[speedplane]

Not sure about that. In the US it seems that the most vocal opponents of gay rights often get caught with their pants down in some embarrassing homosexual encounter.

[peteretep]

Quite. This technology will terrify them.