Index: binaries/data/mods/public/simulation/components/AIProxy.js
===================================================================
--- binaries/data/mods/public/simulation/components/AIProxy.js
+++ binaries/data/mods/public/simulation/components/AIProxy.js
@@ -68,7 +68,7 @@
 		// not yet notified, be sure that the owner is set before doing so
 		// as the Create event is sent only on first ownership changed
 		let cmpOwnership = Engine.QueryInterface(this.entity, IID_Ownership);
-		if (!cmpOwnership || cmpOwnership.GetOwner() < 0)
+		if (!cmpOwnership || cmpOwnership.GetOwner() == INVALID_PLAYER)
 			return false;
 	}
 
Index: binaries/data/mods/public/simulation/components/Fogging.js
===================================================================
--- binaries/data/mods/public/simulation/components/Fogging.js
+++ binaries/data/mods/public/simulation/components/Fogging.js
@@ -160,7 +160,7 @@
 
 Fogging.prototype.IsMiraged = function(player)
 {
-	if (player < 0 || player >= this.mirages.length)
+	if (player == INVALID_PLAYER || player >= this.mirages.length)
 		return false;
 
 	return this.miraged[player];
@@ -168,7 +168,7 @@
 
 Fogging.prototype.GetMirage = function(player)
 {
-	if (player < 0 || player >= this.mirages.length)
+	if (player == INVALID_PLAYER || player >= this.mirages.length)
 		return INVALID_ENTITY;
 
 	return this.mirages[player];
@@ -176,7 +176,7 @@
 
 Fogging.prototype.WasSeen = function(player)
 {
-	if (player < 0 || player >= this.seen.length)
+	if (player == INVALID_PLAYER || player >= this.seen.length)
 		return false;
 
 	return this.seen[player];
@@ -208,7 +208,7 @@
 
 Fogging.prototype.OnVisibilityChanged = function(msg)
 {
-	if (msg.player < 0 || msg.player >= this.mirages.length)
+	if (msg.player == INVALID_PLAYER || msg.player >= this.mirages.length)
 		return;
 
 	if (msg.newVisibility == VIS_VISIBLE)
Index: binaries/data/mods/public/simulation/components/GarrisonHolder.js
===================================================================
--- binaries/data/mods/public/simulation/components/GarrisonHolder.js
+++ binaries/data/mods/public/simulation/components/GarrisonHolder.js
@@ -270,7 +270,7 @@
 {
 	let entityIndex = this.entities.indexOf(entity);
 	// Error: invalid entity ID, usually it's already been ejected
-	if (entityIndex == -1)
+	if (entityIndex == INVALID_ENTITY)
 		return false;
 
 	// Find spawning location
@@ -559,7 +559,7 @@
 
 	// or on some of its garrisoned units
 	let entityIndex = this.entities.indexOf(msg.entity);
-	if (entityIndex != -1)
+	if (entityIndex != INVALID_ENTITY)
 	{
 		// If the entity is dead, remove it directly instead of ejecting the corpse
 		let cmpHealth = Engine.QueryInterface(msg.entity, IID_Health);
@@ -584,7 +584,7 @@
 GarrisonHolder.prototype.OnGlobalEntityRenamed = function(msg)
 {
 	let entityIndex = this.entities.indexOf(msg.entity);
-	if (entityIndex != -1)
+	if (entityIndex != INVALID_ENTITY)
 	{
 		let vgpRenamed;
 		for (let vgp of this.visibleGarrisonPoints)
@@ -611,7 +611,7 @@
 	else
 	{
 		entityIndex = this.initGarrison.indexOf(msg.entity);
-		if (entityIndex != -1)
+		if (entityIndex != INVALID_ENTITY)
 			this.initGarrison[entityIndex] = msg.newentity;
 	}
 };
@@ -645,7 +645,7 @@
 	for (let entity of entities)
 	{
 		let entityIndex = this.entities.indexOf(entity);
-		if (entityIndex == -1)
+		if (entityIndex == INVALID_ENTITY)
 			continue;
 		let cmpHealth = Engine.QueryInterface(entity, IID_Health);
 		if (cmpHealth)