There is a bug with the ASP .NET Web Forms RadioButtonList - if you uncheck all the radios on the client-side (with javascript), after you do a postback the first item in the list will be selected.
For example, try running the following jquery:
$('#myRadioList input').attr('checked', '');
After you do a postback, the first item in the RadioButtonList will be selected.
Anyone know an elegant work around?