Regarding embedding hidden words in these binary images, I'm sometimes alarmed that people seem unaware of how well computer vision can work in restricted scena

Regarding embedding hidden words in these binary images, I'm sometimes alarmed that people seem unaware of how well computer vision can work in restricted scenarios like this. After all, we've had realtime face detectors in cheap cameras for awhile now. It's one thing to prevent spam with captchas but another to protect sensitive information with them.