edited the LobbyLogic to include a spectator toggle in the server admin dropdown.

OpenRA.Game/Network/Session.cs

@@ -127,6 +127,7 @@ namespace OpenRA.Network
 			public int RandomSeed = 0;
 			public bool FragileAlliances = false; // Allow diplomatic stance changes after game start.
 			public bool AllowCheats = false;
+			public bool AllowSpectate = true;
 			public bool Dedicated;
 			public string Difficulty;
 			public bool Crates = true;

OpenRA.Game/Server/Server.cs

@@ -276,6 +276,13 @@ namespace OpenRA.Server
 					IsAdmin = !LobbyInfo.Clients.Any(c1 => c1.IsAdmin)
 				};
 
+				if (client.IsObserver && !LobbyInfo.GlobalSettings.AllowSpectate)
+				{
+					SendOrderTo(newConn, "ServerError", "The game is full");
+					DropClient(newConn);
+					return;
+				}
+
 				if (client.Slot != null)
 					SyncClientToPlayerReference(client, Map.Players[client.Slot]);
 				else

OpenRA.Mods.RA/ServerTraits/LobbyCommands.cs

@@ -132,14 +132,32 @@ namespace OpenRA.Mods.RA.Server
 
 						return true;
 					}},
+				{ "allow_spectate",
+					s =>
+					{
+						s = s.Trim();
+						if(s.Equals("True") || s.Equals("False")){
+							bool.TryParse(s, out server.LobbyInfo.GlobalSettings.AllowSpectate);
+
+							server.SyncLobbyInfo();
+							return true;
+						}else{
+							server.SendOrderTo(conn, "Message", "Malformed allow_spectate command");
+							return true;
+						}
+					}},
 				{ "spectate",
 					s =>
 					{
+						if(server.LobbyInfo.GlobalSettings.AllowSpectate){
 							client.Slot = null;
 							client.SpawnPoint = 0;
 							client.Color = HSLColor.FromRGB(255, 255, 255);
 							server.SyncLobbyInfo();
 							return true;
+						}else{
+							return false;
+						}
 					}},
 				{ "slot_close",
 					s =>

OpenRA.Mods.RA/ServerTraits/MasterServerPinger.cs

@@ -75,7 +75,8 @@ namespace OpenRA.Mods.RA.Server
 								numBots,
 								"{0}@{1}".F(mod.Id, mod.Version),
 								server.LobbyInfo.GlobalSettings.Map,
-								server.Map.PlayerCount));
+								server.Map.PlayerCount,
+								server.LobbyInfo.GlobalSettings.AllowSpectate));
 
 							if (isInitialPing)
 							{

OpenRA.Mods.RA/Widgets/Logic/LobbyLogic.cs

@@ -173,6 +173,7 @@ namespace OpenRA.Mods.RA.Widgets.Logic
 				};
 			}
 
+
 			var slotsButton = lobby.GetOrNull<DropDownButtonWidget>("SLOTS_DROPDOWNBUTTON");
 			if (slotsButton != null)
 			{
@@ -613,6 +614,7 @@ namespace OpenRA.Mods.RA.Widgets.Logic
 				idx++;
 			}
 
+			
 			// Add spectators
 			foreach (var client in orderManager.LobbyInfo.Clients.Where(client => client.Slot == null))
 			{
@@ -656,15 +658,35 @@ namespace OpenRA.Mods.RA.Widgets.Logic
 				// Spectate button
 				if (orderManager.LocalClient.Slot != null)
 				{
+
 					Widget spec = null;
 					if (idx < Players.Children.Count)
 						spec = Players.Children[idx];
 					if (spec == null || spec.Id != NewSpectatorTemplate.Id)
 						spec = NewSpectatorTemplate.Clone();
 
+					var block = spec.Get<ButtonWidget>("BLOCK_SPECTATE");
+					block.OnClick = () =>
+						{
+							orderManager.IssueOrder(Order.Command("allow_spectate False"));
+							orderManager.IssueOrders(
+								orderManager.LobbyInfo.Clients.Where(
+									c => c.IsObserver && !c.IsAdmin).Select(
+										client => Order.Command(String.Format("kick {0} {1}", client.Index, client.Name
+										))).ToArray());
+						};  
+					block.IsVisible = () => orderManager.LocalClient.IsAdmin && orderManager.LobbyInfo.GlobalSettings.AllowSpectate;
+					block.IsDisabled =  () => !orderManager.LobbyInfo.GlobalSettings.AllowSpectate;
+
+					var allow = spec.Get<ButtonWidget>("ALLOW_SPECTATE");
+					allow.OnClick = () => orderManager.IssueOrder(Order.Command("allow_spectate True"));
+					allow.IsVisible = () => orderManager.LocalClient.IsAdmin && !orderManager.LobbyInfo.GlobalSettings.AllowSpectate;
+					allow.IsDisabled = () => orderManager.LobbyInfo.GlobalSettings.AllowSpectate;
+					
 					var btn = spec.Get<ButtonWidget>("SPECTATE");
 					btn.OnClick = () => orderManager.IssueOrder(Order.Command("spectate"));
 					btn.IsDisabled = () => orderManager.LocalClient.IsReady;
+					btn.IsVisible = () => orderManager.LobbyInfo.GlobalSettings.AllowSpectate;
 					spec.IsVisible = () => true;
 					
 					if (idx >= Players.Children.Count)
@@ -675,6 +697,7 @@ namespace OpenRA.Mods.RA.Widgets.Logic
 					idx++;
 				}
 
+
 			while (Players.Children.Count > idx)
 				Players.RemoveChild(Players.Children[idx]);
 		}

mods/cnc/chrome/lobby-playerbin.yaml

@@ -307,10 +307,24 @@ ScrollPanel@LOBBY_PLAYER_BIN:
 			Height:25
 			Visible:false
 			Children:
+				Button@ALLOW_SPECTATE:
+					Text:Allow Spectators
+					Font:Regular
+					Width:190
+					Height:25
+					Y:0
+					X:15
+				Button@BLOCK_SPECTATE:
+					Text:Block Spectators
+					Font:Regular
+					Width:190
+					Height:25
+					Y:0
+					X:15
 				Button@SPECTATE:
 					Text:Spectate
 					Font:Regular
-					Width:453
+					Width:257
 					Height:25
-					X:15
+					X:210
 					Y:0

mods/d2k/chrome/lobby-playerbin.yaml

@@ -298,6 +298,20 @@ ScrollPanel@LOBBY_PLAYER_BIN:
 			Height:25
 			Visible:false
 			Children:
+				Button@ALLOW_SPECTATE:
+					Text:Allow Spectators
+					Font:Regular
+					Width:165
+					Height:25
+					X:15
+					Y:0
+				Button@BLOCK_SPECTATE:
+					Text:Block Spectators
+					Font:Regular
+					Width:165
+					Height:25
+					X:15
+					Y:0
 				Button@SPECTATE:
 					Text:Spectate
 					Font:Regular

mods/ra/chrome/lobby-playerbin.yaml

@@ -298,6 +298,20 @@ ScrollPanel@LOBBY_PLAYER_BIN:
 			Height:25
 			Visible:false
 			Children:
+				Button@ALLOW_SPECTATE:
+					Text:Allow Spectators
+					Font:Regular
+					Width:165
+					Height:25
+					X:15
+					Y:0
+				Button@BLOCK_SPECTATE:
+					Text:Block Spectators
+					Font:Regular
+					Width:165
+					Height:25
+					X:15
+					Y:0
 				Button@SPECTATE:
 					Text:Spectate
 					Font:Regular