My H was the WAS the first time we went through a D. At that time, I insisted on being present the whole time, just so that things didn't disappear that I wanted. Not that he would purposefully take things I wanted, but there were a few things he didn't realize I wanted and we were able to talk about it before he packed it up.
I think if you can avoid R talk and be helpful, then it may be a good thing to help him. If you can't bring yourself to help him, one thing I sometimes did was just go about my business while he did his thing. (I even watched a whole movie while he was there once, except he kept asking me where to find stuff so I had to pause it every few minutes.)
At the time, I think my H thought I did it just to be mean. From the WAS perspective, seeing the one they leave behind is a very uncomfortable reminder of what they're doing and it forces interaction that they may well fear. It's possilble that no matter how cool you are he'll take it the wrong way in the short term, but in the long term it might be for the best. It's a judgment call as to whether it will hurt or help; and it depends on how good your face-to-face DB skills are. (Mine were awful, hence the movie.)
If you think that you can't handle it and you trust that he won't take anything that's important enough you'll have to ask him for later then let him at it and go do something nice for yourself -- window shop, pedicure, whatever.
