I think that defenders with Obliterators should not be shooting when closed in solid boxes, because they should not be able to "magically" aim at Husks. While when using Neon Snipers they should be able to do it, because of "x-ray" scope.
This is exactly the approach we're going to be taking with this. While they can still pierce, they won't be able to pierce as far because the Obliterator doesn't grant vision like the Neon Sniper does.