It doesn't usually though. It only contributes when you're asked to enter house numbers. The usual CAPTCHAs I see from them are the ones coming from their book

It doesn't usually though. It only contributes when you're asked to enter house numbers. The usual CAPTCHAs I see from them are the ones coming from their book scanning project, which I see as a public good. Are there any CAPTCHA providers out there who OSM could team up with to do the same?