Maybe if it can be proven that the person doing the breaking expressly agreed to the site's TOS which contains a clause about CAPTCHAs. This would mean registering on the site. Those footer notices that claim the mere act of visiting the site "constitutes acceptance of TOS" are about as worseless as those email signatures stating not to forward or publish the contents if received by anyone other than the intended recipient.
This would create a very slippery slope. You're essentially giving power to website owners to constitute what is a crime. Anything that breaks their TOS could then be considered a crime.