diff --git a/src/company_cmd.cpp b/src/company_cmd.cpp
index 44993becca..92e3c0d961 100644
--- a/src/company_cmd.cpp
+++ b/src/company_cmd.cpp
@@ -210,6 +210,12 @@ void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cst)
 	if (cost != 0) SubtractMoneyFromAnyCompany(c, CommandCost(cst.GetExpensesType(), cost));
 }
 
+/**
+ * Set the right DParams to get the name of an owner.
+ * @param owner the owner to get the name of.
+ * @param tile  optional tile to get the right town.
+ * @pre if tile == 0, then owner can't be OWNER_TOWN.
+ */
 void GetNameOfOwner(Owner owner, TileIndex tile)
 {
 	SetDParam(2, owner);
@@ -222,6 +228,7 @@ void GetNameOfOwner(Owner owner, TileIndex tile)
 			SetDParam(1, owner);
 		}
 	} else {
+		assert(tile != 0);
 		const Town *t = ClosestTownFromTile(tile, UINT_MAX);
 
 		SetDParam(0, STR_TOWN_NAME);
@@ -230,16 +237,32 @@ void GetNameOfOwner(Owner owner, TileIndex tile)
 }
 
 
-bool CheckOwnership(Owner owner)
+/**
+ * Check whether the current owner owns something.
+ * If that isn't the case an appropriate error will be given.
+ * @param owner the owner of the thing to check.
+ * @param tile  optional tile to get the right town.
+ * @pre if tile == 0 then the owner can't be OWNER_TOWN.
+ * @return true iff it's owned by the current company.
+ */
+bool CheckOwnership(Owner owner, TileIndex tile)
 {
 	assert(owner < OWNER_END);
+	assert(owner != OWNER_TOWN || tile != 0);
 
 	if (owner == _current_company) return true;
 	_error_message = STR_ERROR_OWNED_BY;
-	GetNameOfOwner(owner, 0);
+	GetNameOfOwner(owner, tile);
 	return false;
 }
 
+/**
+ * Check whether the current owner owns the stuff on
+ * the given tile.  If that isn't the case an
+ * appropriate error will be given.
+ * @param tile the tile to check.
+ * @return true iff it's owned by the current company.
+ */
 bool CheckTileOwnership(TileIndex tile)
 {
 	Owner owner = GetTileOwner(tile);
diff --git a/src/functions.h b/src/functions.h
index 81d1872fd3..64684886d0 100644
--- a/src/functions.h
+++ b/src/functions.h
@@ -26,7 +26,7 @@ void TileLoopClearHelper(TileIndex tile);
 bool CheckCompanyHasMoney(CommandCost cost);
 void SubtractMoneyFromCompany(CommandCost cost);
 void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cost);
-bool CheckOwnership(Owner owner);
+bool CheckOwnership(Owner owner, TileIndex tile = 0);
 bool CheckTileOwnership(TileIndex tile);
 
 /* misc functions */
diff --git a/src/road_cmd.cpp b/src/road_cmd.cpp
index 5a5e96257b..a2fde89840 100644
--- a/src/road_cmd.cpp
+++ b/src/road_cmd.cpp
@@ -503,7 +503,7 @@ CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 							if (crossing) return_cmd_error(STR_ERROR_ONEWAY_ROADS_CAN_T_HAVE_JUNCTION);
 
 							Owner owner = GetRoadOwner(tile, ROADTYPE_ROAD);
-							if (owner != OWNER_NONE && !CheckOwnership(owner)) return CMD_ERROR;
+							if (owner != OWNER_NONE && !CheckOwnership(owner, tile)) return CMD_ERROR;
 
 							if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index 0b199bb4e8..bdf7ced771 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -589,7 +589,7 @@ static inline bool CheckAllowRemoveTunnelBridge(TileIndex tile)
 			if (road_owner == OWNER_NONE || road_owner == OWNER_TOWN) road_owner = _current_company;
 			if (tram_owner == OWNER_NONE) tram_owner = _current_company;
 
-			return CheckOwnership(road_owner) && CheckOwnership(tram_owner);
+			return CheckOwnership(road_owner, tile) && CheckOwnership(tram_owner, tile);
 		}
 
 		case TRANSPORT_RAIL: