In a recent post to the FinalConcept blog there's a helpful hint for Symfony developers looking to be rid of a pesky "unexpected form field" error that might pop up - finxing it with a validator.
In this use case we have an exiting model that describes an Article. We want to be able edit the Article and have the option to send and email to an address defined in a text box. However we don't want the email field to be bound to the form and we dont want to add the email address to the Article.
The trick is to add a validator to the form's definition (like a normal field) but to include a "sfValidatorPass" into the validatorSchema and it'll skip right over it. You can find out more about Symfony forms on the Symfony project website.