@Override
    public Element getSubsriptionErrorDetail() {
        return DocumentHelper.createElement(
                QName.get("not-in-roster-group", "http://jabber.org/protocol/pubsub#errors"));
    }
Anyone in the specified roster group(s) may subscribe and retrieve items.

@author Matt Tucker
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/models/RosterAccess.java