title: require explanation if user changed radiobutton between pageload and postback?
body: <p>In my form, someone may make a radio button choice today, but change their mind tomorrow, come back, and make a different radio button choice. If so, they need to explain why they decided to make this change, typing their rationale into a text field.</p>
  
  <p>Is there any way for a CustomValidator on the text field to know the RadioButtonList's choice when the page was loaded, in order to compare it to that same RadioButtonList's choice when the page is submitted?</p>
  
  <p>All of this takes place within a FormView, so worst case scenario, I can use the FormView's ItemUpdating event to look at oldvalues and newvalues, and show/hide a label, but this seemed a little hacky, and I'm wondering if there's a pure validator way to accomplish it.</p>