On https://bugs.freedesktop.org/show_bug.cgi?id=24906#c12 I wrote:

> I've also updated my smcv/conference branch, with:
>
...
> * Handler.FUTURE.RelatedConferencesBypassApproval added, as per discussion in real life (particularly useful for Text UIs)

As a result, Client_Handler_Future.xml contains this:

    <property name="RelatedConferencesBypassApproval"
      tp:name-for-bindings="Related_Conferences_Bypass_Approval"
      type="b" access="read">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>If true, channels destined for this handler that have the
          <tp:dbus-ref namespace="im.telepathy.v1.Channel.Interface"
            >Conference1</tp:dbus-ref> interface, with a channel that
          was previously handled by the same client process in their
          <tp:dbus-ref namespace="im.telepathy.v1.Channel.Interface.Conference1"
            >InitialChannels</tp:dbus-ref> property, should bypass the
          approval stage. In effect, this is a weaker form of
          <tp:dbus-ref namespace="im.telepathy.v1.Client.Handler"
            >BypassApproval</tp:dbus-ref>.</p>

        <tp:rationale>
          <p>It would be reasonable for a user interface to accept
            invitations to continuations of an existing channel automatically,
            or not; this is a matter of UI policy.</p>

          <p>It's somewhat complex for an Approver to keep track of which
            channels are being handled by a particular Handler, but
            the Channel Dispatcher already has to track this, so it's
            useful for the channel dispatcher to assist here.</p>
        </tp:rationale>
      </tp:docstring>
    </property>

As far as I know, this has never been implemented. If we want this, someone needs to implement it.

I'm probably going to delete it from Telepathy 1.0 and someone can put it back if they want it.