Hi Charity,
Simple answer is that Check Boxes and Radio Buttons are different animals. I also leave a return (blank space) if my application is a Menu item that I want a fixed set of data for and would like the option to have "blank". But Menus and Check Boxes are independent logic, meaning they are on or off (yes or no logic) regardless of the status of other Check Box or Menu items in the same list. A Radio Button is either/or allowing one selection of the items in the respective list you have made. The method for creating the list is the same, but the logic use is different, hence the results you are getting. Adding a return should just add some space on the let side of the left circle.
Radio buttons can be cleared by using the delete key, or as you suggest (and I have used for clearing forms) making a Clear Button.
Hope that helps...
-Bob Skye-
