Ion-radio elements can't be disabled

I’m trying to have ion-radio elements be disabled with ng-disabled; it’s not working.
Looking at the Elements in Chrome dev tools the ng-disabled is attached to the ion-radio’s surrounding label element but not to the child input element.
I’ve made an example codepen at
http://codepen.io/rrcook/pen/dKfic

I’d appreciate suggestions for a workaround as well.

I just ran into this issue as well. For reference, I created an issue on Github here. In the meantime, I will be looking for a fix.