By default all of the addOption() methods within the org.dspace.app.xmlui.wing.element.Radio class will set the newly added option as "selected". Despite these methods accepting a "selected" boolean parameter, they never check that parameter in order to determine whether the option should be marked as "selected".
Essentially, they all have the following line:
Whereas, they should have the following:
if (selected) setOptionSelected(returnValue);
This will be fixed shortly in DSpace 1.5.x SVN...just wanted to officially log it as a bug before fixing it.