ngAria : setting aria-invalid to false
<p>Im using ngaria in my angularjs project and I have 3 radio buttons where each has the same ngModel and the values are different.</p>

<pre><code>                &lt;label for="radio"&gt;
                    &lt;input type="radio" value="a" name="someName" id="radio"                              ng-model="someModel"
                           aria-checked="false"&gt;radio one
                &lt;/label&gt;
                &lt;label for="radio2" &gt;
                    &lt;input type="radio" value="b" name="someName"
                           id="radio2" aria-checked="false"                             
                           ng-model="someModel"&gt;radio two
                &lt;/label&gt;
                &lt;label for="radio3"&gt;
                    &lt;input type="radio" value="c" name="someName"
                           id="radio3"
                           aria-checked="false"                             
                           ng-model="someModel"&gt;radio three
                &lt;/label&gt;
</code></pre>

<p>when I check the source via firebug of devtools in chrome, I see that 
<code>aria-invalid</code> is set to false on all of them. Why? I understand that it is because I have ngModel. But why is <code>aria-invalid</code> set to false by default? </p>