I guess it depends on the position - if you have to work with people as a regular part of your position, social skills would be a part of the role, an important one at that.

I'm sorry Dave, I can't do that. (Not GP, but acting the same) I'm looking for candidates I actually want to work with. That includes people with social skills sophisticated enough to freely talk about their prior work.

If a candidate can't do that, they are not a good fit for my company.