Warning message similar to $this->addError()

Hi all,

I'm using a form that submits and validates using AJAX. Is there a method I can use that is similar to addError() except I only want to display a warning message and not prevent the form submitting?

The flow is:

• User enters a number in a form field
  
• The field gets validated by a custom validation function
  
• xxx method returns a warning message - form is still submitable

If there is no YII method for this, any ideas on a good way of writing one?

Thanks!