Got one at Haymarket T this afternoon, after tracking down a friendly T employee. They'd stopped handing them out for the day, but he had an extra one. (Later discovered that they were still handing them out at Davis, but it was still necessary to find the employee and ask for one.)
Tested that my card holder blocked read of the card at a gate, which it did, just like the way it did the SmarTrip card I tested at a Metro faregate. So that's good. Otherwise reads fine, which is also good.
Edit: corrected link to the card holder.