diff --git a/scripts/tests/common.lua b/scripts/tests/common.lua
index a069c7f0a..8e6d66c9f 100755
--- a/scripts/tests/common.lua
+++ b/scripts/tests/common.lua
@@ -955,6 +955,7 @@ function setup()
     eressea.write_game("free.dat")
     eressea.settings.set("rules.economy.food", "4") -- FOOD_IS_FREE
     eressea.settings.set("rules.encounters", "0")
+    eressea.settings.set("rules.move.owner_leave", "0")
 end
 
 function test_parser()
@@ -1257,3 +1258,44 @@ function test_bug_1879_follow_unit()
   assert_equal(u2.region.id, r1.id)
 end
 
+function test_bug_1870_leave_enter_e2()
+  local r = region.create(0, 0, "plain")    
+  local f = faction.create("noreply@eressea.de", "human", "de")
+  local u1, u2 = two_units(r, f, f)
+  local mine = building.create(r, "mine")
+  mine.size = 10
+  u1.building = mine
+
+  local b = building.create(r, "castle")
+  b.size = 10
+  u2.building = b
+    
+  u1:clear_orders()
+  u1:add_order("LERNEN Burgenbau ")
+  u1:add_order("BETRETEN BURG " .. itoa36(b.id))
+
+  eressea.settings.set("rules.move.owner_leave", "0")
+  process_orders()
+  assert_equal(u1.building.id, b.id)
+end
+
+function test_bug_1870_leave_enter_e3()
+  local r = region.create(0, 0, "plain")    
+  local f = faction.create("noreply@eressea.de", "human", "de")
+  local u1, u2 = two_units(r, f, f)
+  local mine = building.create(r, "mine")
+  mine.size = 10
+  u1.building = mine
+
+  local b = building.create(r, "castle")
+  b.size = 10
+  u2.building = b
+    
+  u1:clear_orders()
+  u1:add_order("LERNEN Burgenbau ")
+  u1:add_order("BETRETEN BURG " .. itoa36(b.id))
+
+  eressea.settings.set("rules.move.owner_leave", "1")
+  process_orders()
+  assert_equal(u1.building.id, mine.id)
+end
diff --git a/src/gamecode/laws.c b/src/gamecode/laws.c
index ac77a3c97..cf43535d8 100755
--- a/src/gamecode/laws.c
+++ b/src/gamecode/laws.c
@@ -1261,9 +1261,11 @@ int enter_ship(unit * u, struct order *ord, int id, int report)
     }
   }
 
-  if (leave(u, 0)) {
+  if (leave(u, false)) {
     u_set_ship(u, sh);
     fset(u, UFL_ENTER);
+  } else if (report) {
+    cmistake(u, ord, 150, MSG_MOVE);
   }
   return 1;
 }
@@ -1310,6 +1312,8 @@ int enter_building(unit * u, order * ord, int id, int report)
     fset(u, UFL_ENTER);
     u_set_building(u, b);
     return 1;
+  } else if (report) {
+    cmistake(u, ord, 150, MSG_MOVE);
   }
   return 0;
 }
diff --git a/src/kernel/unit.c b/src/kernel/unit.c
index 5aee29ab7..16901d34b 100644
--- a/src/kernel/unit.c
+++ b/src/kernel/unit.c
@@ -822,14 +822,18 @@ void leave_building(unit * u)
 
 bool can_leave(unit * u)
 {
+  static int gamecookie = -1;
   static int rule_leave = -1;
 
   if (!u->building) {
     return true;
   }
-  if (rule_leave < 0) {
+
+  if (rule_leave < 0 || gamecookie != global.cookie) {
+    gamecookie = global.cookie;
     rule_leave = get_param_int(global.parameters, "rules.move.owner_leave", 0);
   }
+
   if (rule_leave && u->building && u == building_owner(u->building)) {
     return false;
   }