Clarify that set noparent should be rarely used

[email protected]

Change-Id: I049857e9eb094d60e153074b361dab7146a13623
Reviewed-on: https://chromium-review.googlesource.com/596968
Commit-Queue: Brett Wilson <[email protected]>
Reviewed-by: Brett Wilson <[email protected]>
Cr-Commit-Position: refs/heads/master@{#491425}
diff --git a/docs/code_reviews.md b/docs/code_reviews.md
index af8e91e..340380a 100644
--- a/docs/code_reviews.md
+++ b/docs/code_reviews.md
@@ -192,8 +192,10 @@
 ```
 
 The text `set noparent` will stop owner propagation from parent directories.
-This is used for specialized code. In this example, only the two listed people
-are owners:
+This should be rarely used. If you want to use `set noparent` except for IPC
+related files, please first reach out to [email protected].
+
+In this example, only the two listed people are owners:
 ```
 set noparent
 [email protected]