diff --git a/docs/TODO b/docs/TODO
index d56af9235..656da2aa7 100644
--- a/docs/TODO
+++ b/docs/TODO
@@ -36,6 +36,11 @@ o Device categorization improvements
 o Joao is auditing his Lua code to make sure all his variables are
   local where appropriate. [Joao]
 
+o [NSE] We should document somewhere in scripting.xml the dangers inherent
+  in global variables and warn people to generally declare them local
+  instead.  We have a long history of bugs caused by non-local
+  variables defined in NSE libraies and often causing deadlocks.
+
 o Consider the open proxy scripts more carefully
  - How should we test whether the proxy attempt was successful?  Right
    now we look for a google-specific Server header after trying to