Double Bluff HoneyPot

Trying to avoid form CAPTCHAs, so considering implementation of a "Double Bluff" honeypot to stop spam. Goes like this: CSS hidden, traditional honeypot input with a tempting name like 'title' that's empty for robots to inadvertently fill. Then a hidden input that is javascript filled once page has loaded. Checking the first pot is empty and the second full should capture all but the mightest spam routine...