Store time in hidden form field instead of session

[ThomasLandauer]

I'm thinking about a way to prevent a session from being started for all users automatically (if timed is activated). Here's an idea: http://vvv.tobiassjosten.net/symfony/stopping-spam-with-symfony-forms/

In short: Store the current time in a hidden form field (obfuscated by some sort of "encryption") instead of the session.