diff --git a/src/environment.cpp b/src/environment.cpp
index 17b98acd1..6d987e3c2 100644
--- a/src/environment.cpp
+++ b/src/environment.cpp
@@ -194,7 +194,8 @@ void Environment::addPlayer(Player *player)
 #ifndef SERVER
 	assert(player->isLocal() == false || getLocalPlayer() == NULL);
 #endif
-	assert(getPlayer(player->peer_id) == NULL);
+	if(player->peer_id != 0)
+		assert(getPlayer(player->peer_id) == NULL);
 	m_players.push_back(player);
 }
 
diff --git a/src/environment.h b/src/environment.h
index 03f366b47..fa7253170 100644
--- a/src/environment.h
+++ b/src/environment.h
@@ -73,6 +73,8 @@ public:
 
 private:
 	Map *m_map;
+	// peer_ids in here should be unique, except that there may be
+	// many 0s
 	core::list<Player*> m_players;
 	// Debug output goes here
 	std::ostream &m_dout;