that would actually be cool, and an useful use of captchas, for once.
Because they want to punish those who dare to use firefox without changing the user agent?
For sensitive material, we would often insta-ban anyone who hit us with a 'curl' user-agent and that definitely killed a lot of script-kiddies' dreams right then and there.
Obviously, if you are a determined "hacker" you would get past that and hit the honeypots but simple filters could filter out enough scrapers such that the rest of the attacks could be manually evaluated by humans.