public boolean isVoiceOnly() {
        return voiceOnly;
    }
Returns true if the room occupant does not want to get messages broadcast to all
room occupants. This type of users are called "deaf" occupants. Deaf occupants will still
be able to get private messages, presences, IQ packets or room history.<p>

To be a deaf occupant the initial presence sent to the room while joining the room has
to include the following child element:
<pre>
&lt;x xmlns='http://jivesoftware.org/protocol/muc'&gt;
    &lt;deaf-occupant/&gt;
&lt;/x&gt;
</pre>

Note that this is a custom extension to the MUC specification.

@return true if the room occupant does not want to get messages broadcasted to all
        room occupants.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCOccupant.java