Redundant test for duplicate membership in Group.addMember

int bestCount = membershipSizeThreshold;
        PropertyState bestProperty = null;
        Tree bestTree = null;
        while (trees.hasNext()) {
            Tree t = trees.next();
            PropertyState refs = t.getProperty(UserConstants.REP_MEMBERS);
            if (refs != null) {
                int numRefs = 0;
                for (String ref : refs.getValue(Type.WEAKREFERENCES)) {
                    if (ref.equals(memberContentId)) {
                        return false;
                    }
                    numRefs++;
                }
                if (numRefs < bestCount) {
                    bestCount = numRefs;
                    bestProperty = refs;
                    bestTree = t;
                }
            }
        }