I was hacking around with the echo bot+butterfly, and found that TargetID was missing from the properties returned when I requested a StreamedMedia channel. I think this is where it's happening, but I was supposed to be working on tp-glib bugs, so this was as far as I got.

diff --git a/src/server/conn.py b/src/server/conn.py
index 0ef2206..7e933d6 100644
--- a/src/server/conn.py
+++ b/src/server/conn.py
@@ -520,6 +520,9 @@ class ConnectionInterfaceRequests(
         for p in todel:
             del props[p]
 
+        # http://telepathy.freedesktop.org/spec/org.freedesktop.Telepathy.Connection.Interface.Requests.html
+        # says that we MUST include ChannelType, TargetHandleType, TargetHandle, TargetID, and Requested.
+        # We currently strip out TargetID. This is bad.
         _success(channel._object_path, props)
 
         # CreateChannel MUST return *before* NewChannels is emitted.