diff --git a/OpenRA.Game/Actor.cs b/OpenRA.Game/Actor.cs
index c7605549bc..e4378cee19 100644
--- a/OpenRA.Game/Actor.cs
+++ b/OpenRA.Game/Actor.cs
@@ -30,7 +30,7 @@ namespace OpenRA
 
 		public readonly uint ActorID;
 
-		[Sync] public Player Owner { get; set; }
+		public Player Owner { get; set; }
 
 		public bool IsInWorld { get; internal set; }
 		public bool Disposed { get; private set; }
diff --git a/OpenRA.Game/Traits/World/Shroud.cs b/OpenRA.Game/Traits/World/Shroud.cs
index baeddde339..cd3dc6f125 100644
--- a/OpenRA.Game/Traits/World/Shroud.cs
+++ b/OpenRA.Game/Traits/World/Shroud.cs
@@ -20,7 +20,7 @@ namespace OpenRA.Traits
 		public object Create(ActorInitializer init) { return new Shroud(init.Self); }
 	}
 
-	public class Shroud
+	public class Shroud : ISync
 	{
 		[Sync] public bool Disabled;
 
diff --git a/OpenRA.Mods.Common/Effects/GravityBomb.cs b/OpenRA.Mods.Common/Effects/GravityBomb.cs
index 2038ad1017..a81e347947 100644
--- a/OpenRA.Mods.Common/Effects/GravityBomb.cs
+++ b/OpenRA.Mods.Common/Effects/GravityBomb.cs
@@ -38,7 +38,7 @@ namespace OpenRA.Mods.Common.Effects
 		public IEffect Create(ProjectileArgs args) { return new GravityBomb(this, args); }
 	}
 
-	public class GravityBomb : IEffect
+	public class GravityBomb : IEffect, ISync
 	{
 		readonly GravityBombInfo info;
 		readonly Animation anim;
diff --git a/OpenRA.Mods.Common/Lint/CheckSyncAnnotations.cs b/OpenRA.Mods.Common/Lint/CheckSyncAnnotations.cs
index 9215590ec2..d2ebd50715 100644
--- a/OpenRA.Mods.Common/Lint/CheckSyncAnnotations.cs
+++ b/OpenRA.Mods.Common/Lint/CheckSyncAnnotations.cs
@@ -9,6 +9,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using OpenRA.Traits;
@@ -19,23 +20,43 @@ namespace OpenRA.Mods.Common.Lint
 	{
 		public void Run(Action<string> emitError, Action<string> emitWarning)
 		{
-			/* first, check all the types implementing ISync */
-			foreach (var t in Game.ModData.ObjectCreator.GetTypesImplementing<ISync>())
-				if (!HasAnySyncFields(t))
-					emitWarning("{0} has ISync but nothing marked with [Sync]".F(t.Name));
+			var modTypes = Game.ModData.ObjectCreator.GetTypes();
+			CheckTypesWithSyncableMembersImplementSyncInterface(modTypes, emitWarning);
+			CheckTypesImplementingSyncInterfaceHaveSyncableMembers(modTypes, emitWarning);
 		}
 
-		bool HasAnySyncFields(Type t)
+		static readonly Type SyncInterface = typeof(ISync);
+
+		static bool TypeImplementsSync(Type type)
 		{
-			var flags = BindingFlags.Public | BindingFlags.NonPublic
-				| BindingFlags.Instance;
+			return type.GetInterfaces().Contains(SyncInterface);
+		}
 
-			var fs = t.GetFields(flags);
-			var ps = t.GetProperties(flags);
+		static bool AnyTypeMemberIsSynced(Type type)
+		{
+			const BindingFlags Flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly;
+			while (type != null)
+			{
+				if (((MemberInfo[])type.GetFields(Flags)).Concat(type.GetProperties(Flags)).Any(x => x.HasAttribute<SyncAttribute>()))
+					return true;
+				type = type.BaseType;
+			}
 
-			return fs.Any(f => f.HasAttribute<SyncAttribute>()) ||
-				ps.Any(p => p.HasAttribute<SyncAttribute>()) ||
-				HasAnySyncFields(t.BaseType);
+			return false;
+		}
+
+		static void CheckTypesWithSyncableMembersImplementSyncInterface(IEnumerable<Type> types, Action<string> emitWarning)
+		{
+			foreach (var type in types)
+				if (!TypeImplementsSync(type) && AnyTypeMemberIsSynced(type))
+					emitWarning("{0} has members with the Sync attribute but does not implement ISync".F(type.FullName));
+		}
+
+		static void CheckTypesImplementingSyncInterfaceHaveSyncableMembers(IEnumerable<Type> types, Action<string> emitWarning)
+		{
+			foreach (var type in types)
+				if (TypeImplementsSync(type) && !AnyTypeMemberIsSynced(type))
+					emitWarning("{0} implements ISync but does not use the Sync attribute on any members.".F(type.FullName));
 		}
 	}
-}
+}
\ No newline at end of file
diff --git a/OpenRA.Mods.Common/Traits/ExternalCapturable.cs b/OpenRA.Mods.Common/Traits/ExternalCapturable.cs
index ccc4fc8741..a4949a7fe5 100644
--- a/OpenRA.Mods.Common/Traits/ExternalCapturable.cs
+++ b/OpenRA.Mods.Common/Traits/ExternalCapturable.cs
@@ -49,7 +49,7 @@ namespace OpenRA.Mods.Common.Traits
 		public object Create(ActorInitializer init) { return new ExternalCapturable(init.Self, this); }
 	}
 
-	public class ExternalCapturable : ITick
+	public class ExternalCapturable : ITick, ISync
 	{
 		[Sync] public int CaptureProgressTime = 0;
 		[Sync] public Actor Captor;
diff --git a/OpenRA.Mods.Common/Traits/ParaDrop.cs b/OpenRA.Mods.Common/Traits/ParaDrop.cs
index f9a5999b30..79dad067bd 100644
--- a/OpenRA.Mods.Common/Traits/ParaDrop.cs
+++ b/OpenRA.Mods.Common/Traits/ParaDrop.cs
@@ -27,7 +27,7 @@ namespace OpenRA.Mods.Common.Traits
 		public object Create(ActorInitializer init) { return new ParaDrop(init.Self, this); }
 	}
 
-	public class ParaDrop : ITick, INotifyRemovedFromWorld
+	public class ParaDrop : ITick, ISync, INotifyRemovedFromWorld
 	{
 		readonly ParaDropInfo info;
 		readonly Actor self;