Well, I found that and thought the same thing, but it does not work on page refresh using IE. Other browsers provide different results.
Here is what I have found.
Internet Explorer nothing works unless I delete browsing history after selecting radio button two or highlight the address bar contents and hit enter which I consider a page load rather then page refresh.
Firefox works like Internet Explorer, page refresh does nothing, page load puts the tick back on radio button one.
Chrome everything works as it should.
Microsoft Edge works a little differently. On page refresh, the tick is on radio button one for a split second then disappears leaving both radio buttons unchecked. Page load puts the tick back on radio button one.
I've tried the autocomplete="off", checked="false", checked="unchecked" and various javascripts and jQuery + javascripts and nothing seems to work for IE and the other browsers.
Seems if I delete browsing history it works or page load by highlighting the address bar and hit enter it works.
I think informing our business customers of the situation maybe the best solution at this point.