--- a/Lists.lua	Wed Mar 07 23:01:33 2012 -0500
+++ b/Lists.lua	Thu Mar 08 08:30:24 2012 -0500
@@ -331,6 +331,10 @@
     -- require admin
     local listIndex = bsk:GetListIndex(list)
     local id = personsReverse[name]
+    if bsk:IdIsInList(id,bsk.lists[listIndex]) then
+        bsk:Print(sformat("Person %s is already on the reqeuested list",name))
+        return
+    end
     bsk:Print(sformat("Adding %s (%s) to list %s (%s)", name, id, list, listIndex))
     local change = {action="AddToListEnd",arg={id=id,listIndex=listIndex}}
     bsk:StartChange(change)
@@ -357,6 +361,10 @@
         self:Print("Cannot add person to list by random roll because an add-to-end operation has already occurred")
         return false
     end
+    if bsk:IdIsInList(id,bsk.lists[listIndex]) then
+        bsk:Print(sformat("Person %s is already on the reqeuested list",name))
+        return
+    end
     local id = personsReverse[name]
     local roll = math.random()
     bsk:Print(sformat("Adding %s (%s) to list %s (%s) with roll (%f)", name, id, list, listIndex, roll))
@@ -559,6 +567,15 @@
     return ret
 end
 
+function bsk:IdIsInList(id,listRef)
+    for i = 1,#listRef do
+        if id == listRef[i].id then
+            return true
+        end
+    end
+    return false
+end
+
 -- returns true if the events in the list are in time order
 function bsk:CheckListCausality()
     local t = nil