Hi matty04,
I don’t know the answer to your question, but there is a plugin designed for use with Formidable Forms, that I think uses a similar approach. It’s called Formidable Honeypot http://wordpress.org/plugins/formidable-honeypot/
Karen
As of right now, no. There’s not default support for Formidable. You can however easily integrate it into any theme or plugin using it’s helpers. See the readme for more info.
Also, feel free to submit a feature request here: https://github.com/bmarshall511/wordpress-zero-spam/issues
