diff --git a/OpenSim/Framework/IScene.cs b/OpenSim/Framework/IScene.cs
index 6919c48d91..e0e023d76c 100644
--- a/OpenSim/Framework/IScene.cs
+++ b/OpenSim/Framework/IScene.cs
@@ -74,9 +74,7 @@ namespace OpenSim.Framework
         /// <param name="client"></param>
         /// <param name="type">The type of agent to add.</param>
         /// <returns>
-        /// The scene agent if the new client was added.
-        /// Null if the required scene agent already existed or no scene agent was added because the required client circuit doesn't exist.
-        /// </returns>
+        /// The scene agent if the new client was added or if an agent that already existed.</returns>
         ISceneAgent AddNewClient(IClientAPI client, PresenceType type);
 
         /// <summary>
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
index 7db5f6bc5b..4ab8fd02fd 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
@@ -897,12 +897,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             IClientAPI client = AddNewClient((UseCircuitCodePacket)packet, remoteEndPoint);
 
             // Send ack straight away to let the viewer know that the connection is active.
+            // The client will be null if it already exists (e.g. if on a region crossing the client sends a use
+            // circuit code to the existing child agent.  This is not particularly obvious.
             SendAckImmediate(remoteEndPoint, packet.Header.Sequence);
 
-            // FIXME: Nasty - this is the only way we currently know if Scene.AddNewClient() failed to find a
-            // circuit and bombed out early.  That check might be pointless since authorization is established
-            // up here.
-            if (client != null && client.SceneAgent != null)
+            // We only want to send initial data to new clients, not ones which are being converted from child to root.
+            if (client != null)
                 client.SceneAgent.SendInitialDataToMe();
 
             //            m_log.DebugFormat(
diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index d47536a866..11505cc040 100644
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -2486,21 +2486,14 @@ namespace OpenSim.Region.Framework.Scenes
 
         #region Add/Remove Avatar Methods
 
-        /// <summary>
-        /// Add a new client and create a child scene presence for it.
-        /// </summary>
-        /// <param name="client"></param>
-        /// <param name="type">The type of agent to add.</param>
         public override ISceneAgent AddNewClient(IClientAPI client, PresenceType type)
         {
+            // Validation occurs in LLUDPServer
             AgentCircuitData aCircuit = m_authenticateHandler.GetAgentCircuitData(client.CircuitCode);
-            bool vialogin = false;
 
-            if (aCircuit == null) // no good, didn't pass NewUserConnection successfully
-                return null;
-
-            vialogin = (aCircuit.teleportFlags & (uint)Constants.TeleportFlags.ViaHGLogin) != 0 || 
-                       (aCircuit.teleportFlags & (uint)Constants.TeleportFlags.ViaLogin) != 0;
+            bool vialogin
+                = (aCircuit.teleportFlags & (uint)Constants.TeleportFlags.ViaHGLogin) != 0
+                    || (aCircuit.teleportFlags & (uint)Constants.TeleportFlags.ViaLogin) != 0;
 
             CheckHeartbeat();
 
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index 6463ab10dd..882492178e 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -2548,7 +2548,7 @@ namespace OpenSim.Region.Framework.Scenes
             }
             
             // This agent just became root. We are going to tell everyone about it. The process of
-            // getting other avatars information was initiated in the constructor... don't do it 
+            // getting other avatars information was initiated elsewhere immediately after the child circuit connected... don't do it
             // again here... this comes after the cached appearance check because the avatars
             // appearance goes into the avatar update packet
             SendAvatarDataToAllAgents();