Radio button checked attribute doesn't work

[mdwyer]

I have this weird problem where a radio button with the 'checked' attribute does not show the button checked. Here's the code:

<td><input name=x type=radio value=0 checked>N
<input name=x type=radio value=1 >C
</td>

The output is:
( )N ( )C

when it should be:
(@)N ( )C

(loosely rendered


I included the <td> tags in case embedding the radio buttons inside a table sheds some light. Also, the table is being populated within a CSP loop through a user plugin collection.

Any ideas would be appreciated.