I have created a number of radio button fields on objects which are optional fields. it appears that if a user accidentally clicks one of the choices, there is no way to negate the value except to reload/refresh the screen. is there any other way to do this?
It seems like you're right, there is no way in HTML to clear radio buttons selection. You can provide an extra option "No selection". This has nothing to do with Rollbase, just generic HTML issue.
You could also use JavaScript. Create a link "Clear Buttons" that when clicked, calls a JavaScript function to clear the button group. Here's an example: http://jennifermadden.com/javascript/loopRadioClear.html