validates_acceptance_of with virtual attribute check box

I've scoured the web for solution, but I can't figure out why this is not working! I have a terms and conditions check box that user has to check in order to register with a site, but it seems to just let user register regardless of the check box status.

Here's what I have:

Never mind.. I found out that at "save", terms_and_conditions was not being set and that was the problem! Everything works fine now.