[samuellevy]

I just label my fields appropriately, and put a "skip to form" link (like a "skip to content" link). Other options exist like using media detection, or JavaScript (very few bots run JavaScript on pages. It slows down the process, and requires more smarts than a generic html parser)

No negative captcha will stand up to a targeted attack, but if you're not running a huge site, targeted attacks are very unlikely.