AngularJS: changing non-bindable selected attribute

Although the div has the ng:non-bindable attribute set, Angular is changing the selected="true" attribute to selected="selected". Click "Check it" to see...

HTML

<script src="https://raw.github.com/msgilligan/msgilligan.github.com/master/samples/angular-bootstrap/js/angular-0.10.7-b9bcc0f6.js"></script>
<div ng:controller="Ctrl">
    <a ng-click="checkAttr()">Check it</a>
</div>
<div id="dont-touch" ng:non-bindable selected="true">
</div>

JavaScript

function Ctrl($scope) {
    $scope.checkAttr = function() {
        alert(document.getElementById('dont-touch').getAttribute('selected'));      
    };
}