diff -Nurd -X.diff_ignore freeciv/server/sanitycheck.c freeciv/server/sanitycheck.c
--- freeciv/server/sanitycheck.c	2012-06-25 00:39:30.000000000 +0300
+++ freeciv/server/sanitycheck.c	2012-08-17 03:33:52.000000000 +0300
@@ -424,6 +424,11 @@
         /* Transporter capacity will be checked when transporter itself
          * is checked */
       }
+
+      /* Check that cargo is marked as transported with this unit */
+      unit_list_iterate(unit_transport_cargo(punit), pcargo) {
+        SANITY_CHECK(unit_transport_get(pcargo) == punit);
+      } unit_list_iterate_end;
     } unit_list_iterate_end;
   } players_iterate_end;
 }