Well, yes, they will, I think, still have the +4 benefit of cover, or the 20% miss chance of concealment, if one of those were used to Hide (usually the case, I agree), but I do not believe that means they are hidden anymore- to me, that means NOT knowing where they are standing- cover and concealment are different, not lesser types of Hide. They do not permit sniping in this scenario, for example, in my view.