diff --git a/arena.go b/arena.go
index 6162238..0b2e85b 100644
--- a/arena.go
+++ b/arena.go
@@ -174,13 +174,13 @@ func (arena *Arena) AssignTeam(teamId int, station string) error {
 		return nil
 	}
 
-	// Load the team model. Raise an error if a team doesn't exist.
+	// Load the team model. If it doesn't exist, enable anonymous operation.
 	team, err := db.GetTeamById(teamId)
 	if err != nil {
 		return err
 	}
 	if team == nil {
-		return fmt.Errorf("Invalid team number '%d'.", teamId)
+		team = &Team{Id: teamId}
 	}
 
 	arena.AllianceStations[station].team = team
diff --git a/arena_test.go b/arena_test.go
index cb5df02..3762b2a 100644
--- a/arena_test.go
+++ b/arena_test.go
@@ -48,12 +48,6 @@ func TestAssignTeam(t *testing.T) {
 	err = dsConn.conn.Close()
 	assert.NotNil(t, err) // Connection should have already been closed.
 
-	// Check assigning an unknown team.
-	err = mainArena.AssignTeam(1503, "R1")
-	if assert.NotNil(t, err) {
-		assert.Contains(t, err.Error(), "Invalid team number")
-	}
-
 	// Check assigning zero as the team number.
 	err = mainArena.AssignTeam(0, "R2")
 	assert.Nil(t, err)
@@ -451,10 +445,6 @@ func TestSubstituteTeam(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, 101, mainArena.currentMatch.Blue1)
 	assert.Equal(t, 101, mainArena.AllianceStations["B1"].team.Id)
-	err = mainArena.SubstituteTeam(1503, "R1")
-	if assert.NotNil(t, err) {
-		assert.Contains(t, err.Error(), "Invalid team number")
-	}
 	err = mainArena.AssignTeam(104, "R4")
 	if assert.NotNil(t, err) {
 		assert.Contains(t, err.Error(), "Invalid alliance station")