I've seen stuff like this in use for domain specific knowledge for forums for years - either there is a near infinite question pool or you're reduced down to something that's broken easily given a site-specific bot.
Over 10 years ago, off the shelf forum spam software, Xrumer, would build a database of these questions for you when it detected the field on a /register page. Since basically every website has a small, finite pool of questions (usually just one), you'd just sit down, answer them all, and then click "resume".