And handle the other way to globally register an entity

common/cpw/mods/fml/common/registry/EntityRegistry.java

@@ -179,8 +179,7 @@ public class EntityRegistry
             }
             else
             {
-                FMLLog.severe("There is a rogue mod trying to register entities from outside the context of mod loading. This is incredibly dangerous and should be stopped.");
-                Thread.dumpStack();
+                FMLLog.severe("There is a rogue mod failing to register entities from outside the context of mod loading. This is incredibly dangerous and should be stopped.");
             }
             FMLLog.warning("The mod %s tried to register the entity class %s which was already registered - if you wish to override default naming for FML mod entities, register it here first", modId, entityClass);
             return;
@@ -222,6 +221,21 @@ public class EntityRegistry
 
     public static void registerGlobalEntityID(Class <? extends Entity > entityClass, String entityName, int id, int backgroundEggColour, int foregroundEggColour)
     {
+        if (EntityList.field_75626_c.containsKey(entityClass))
+        {
+            ModContainer activeModContainer = Loader.instance().activeModContainer();
+            String modId = "unknown";
+            if (activeModContainer != null)
+            {
+                modId = activeModContainer.getModId();
+            }
+            else
+            {
+                FMLLog.severe("There is a rogue mod failing to register entities from outside the context of mod loading. This is incredibly dangerous and should be stopped.");
+            }
+            FMLLog.warning("The mod %s tried to register the entity class %s which was already registered - if you wish to override default naming for FML mod entities, register it here first", modId, entityClass);
+            return;
+        }
         instance().validateAndClaimId(id);
         EntityList.func_75614_a(entityClass, entityName, id, backgroundEggColour, foregroundEggColour);
     }