diff --git a/OpenRA.Game/Player.cs b/OpenRA.Game/Player.cs
index 444ea4ca9d..22d6378dc1 100644
--- a/OpenRA.Game/Player.cs
+++ b/OpenRA.Game/Player.cs
@@ -229,8 +229,6 @@ namespace OpenRA
 			return "{0} ({1})".F(PlayerName, ClientIndex);
 		}
 
-		public Dictionary<Player, PlayerRelationship> Stances = new Dictionary<Player, PlayerRelationship>();
-
 		public PlayerRelationship RelationshipWith(Player other)
 		{
 			if (this == other)
@@ -240,7 +238,13 @@ namespace OpenRA
 			if (other == null || other.Spectating)
 				return NonCombatant ? PlayerRelationship.Neutral : PlayerRelationship.Ally;
 
-			return Stances[other];
+			if (AlliedPlayersMask.Overlaps(other.PlayerMask))
+				return PlayerRelationship.Ally;
+
+			if (EnemyPlayersMask.Overlaps(other.PlayerMask))
+				return PlayerRelationship.Enemy;
+
+			return PlayerRelationship.Neutral;
 		}
 
 		public bool IsAlliedWith(Player p)
diff --git a/OpenRA.Game/World.cs b/OpenRA.Game/World.cs
index ebae869dba..a39218adb0 100644
--- a/OpenRA.Game/World.cs
+++ b/OpenRA.Game/World.cs
@@ -207,30 +207,13 @@ namespace OpenRA
 			Selection = WorldActor.Trait<ISelection>();
 			OrderValidators = WorldActor.TraitsImplementing<IValidateOrder>().ToArray();
 
-			// Reset mask
 			LongBitSet<PlayerBitMask>.Reset();
 
-			// Add players
 			// Create an isolated RNG to simplify synchronization between client and server player faction/spawn assignments
 			var playerRandom = new MersenneTwister(orderManager.LobbyInfo.GlobalSettings.RandomSeed);
 			foreach (var cmp in WorldActor.TraitsImplementing<ICreatePlayers>())
 				cmp.CreatePlayers(this, playerRandom);
 
-			// Set defaults for any unset stances
-			foreach (var p in Players)
-			{
-				if (!p.Spectating)
-					AllPlayersMask = AllPlayersMask.Union(p.PlayerMask);
-
-				foreach (var q in Players)
-				{
-					SetUpPlayerMask(p, q);
-
-					if (!p.Stances.ContainsKey(q))
-						p.Stances[q] = PlayerRelationship.Neutral;
-				}
-			}
-
 			Game.Sound.SoundVolumeModifier = 1.0f;
 
 			gameInfo = new GameInformation
@@ -245,25 +228,6 @@ namespace OpenRA
 			RulesContainTemporaryBlocker = map.Rules.Actors.Any(a => a.Value.HasTraitInfo<ITemporaryBlockerInfo>());
 		}
 
-		void SetUpPlayerMask(Player p, Player q)
-		{
-			if (q.Spectating)
-				return;
-
-			var bitSet = q.PlayerMask;
-
-			switch (p.Stances[q])
-			{
-				case PlayerRelationship.Enemy:
-				case PlayerRelationship.Neutral:
-					p.EnemyPlayersMask = p.EnemyPlayersMask.Union(bitSet);
-					break;
-				case PlayerRelationship.Ally:
-					p.AlliedPlayersMask = p.AlliedPlayersMask.Union(bitSet);
-					break;
-			}
-		}
-
 		public void AddToMaps(Actor self, IOccupySpace ios)
 		{
 			ActorMap.AddInfluence(self, ios);
diff --git a/OpenRA.Mods.Common/Traits/World/CreateMPPlayers.cs b/OpenRA.Mods.Common/Traits/World/CreateMPPlayers.cs
index f1ea9fa4d7..2a6a0c78e2 100644
--- a/OpenRA.Mods.Common/Traits/World/CreateMPPlayers.cs
+++ b/OpenRA.Mods.Common/Traits/World/CreateMPPlayers.cs
@@ -132,23 +132,25 @@ namespace OpenRA.Mods.Common.Traits
 
 			foreach (var p in w.Players)
 				foreach (var q in w.Players)
-					if (!p.Stances.ContainsKey(q))
-						p.Stances[q] = ChooseInitialStance(p, q);
+					SetupPlayerMasks(p, q);
 		}
 
-		static PlayerRelationship ChooseInitialStance(Player p, Player q)
+		static void SetupPlayerMasks(Player p, Player q)
 		{
-			if (p == q)
-				return PlayerRelationship.Ally;
+			if (!p.Spectating)
+				p.World.AllPlayersMask = p.World.AllPlayersMask.Union(p.PlayerMask);
 
-			if (q.Spectating && !p.NonCombatant && p.Playable)
-				return PlayerRelationship.Ally;
+			if (p == q || p.PlayerReference.Allies.Contains(q.InternalName))
+			{
+				p.AlliedPlayersMask = p.AlliedPlayersMask.Union(q.PlayerMask);
+				return;
+			}
 
-			// Stances set via PlayerReference
-			if (p.PlayerReference.Allies.Contains(q.InternalName))
-				return PlayerRelationship.Ally;
 			if (p.PlayerReference.Enemies.Contains(q.InternalName))
-				return PlayerRelationship.Enemy;
+			{
+				p.EnemyPlayersMask = p.EnemyPlayersMask.Union(q.PlayerMask);
+				return;
+			}
 
 			// HACK: Map players share a ClientID with the host, so would
 			// otherwise take the host's team stance instead of being neutral
@@ -158,12 +160,13 @@ namespace OpenRA.Mods.Common.Traits
 				var pc = GetClientForPlayer(p);
 				var qc = GetClientForPlayer(q);
 				if (pc != null && qc != null)
-					return pc.Team != 0 && pc.Team == qc.Team
-						? PlayerRelationship.Ally : PlayerRelationship.Enemy;
+				{
+					if (pc.Team != 0 && pc.Team == qc.Team)
+						p.AlliedPlayersMask = p.AlliedPlayersMask.Union(q.PlayerMask);
+					else
+						p.EnemyPlayersMask = p.EnemyPlayersMask.Union(q.PlayerMask);
+				}
 			}
-
-			// Otherwise, default to neutral
-			return PlayerRelationship.Neutral;
 		}
 
 		static Session.Client GetClientForPlayer(Player p)