diff --git a/doc.zih.tu-dresden.de/util/grep-forbidden-patterns.sh b/doc.zih.tu-dresden.de/util/grep-forbidden-patterns.sh
index f3cfa673ce063a674cb2f850d7f7da252a6ab093..4dfba33d1a073ba3b4b7e976bc822d822f630030 100755
--- a/doc.zih.tu-dresden.de/util/grep-forbidden-patterns.sh
+++ b/doc.zih.tu-dresden.de/util/grep-forbidden-patterns.sh
@@ -40,6 +40,9 @@ i	\<todo\>	<!--.*todo.*-->
 Replace variations of \"Coming soon\" with real content.
 
 i	\(\<coming soon\>\|This .* under construction\|posted here\)
+Add table column headers.
+
+i	^[ |]*|$
 Avoid spaces at end of lines.
 doc.zih.tu-dresden.de/docs/accessibility.md
 i	[[:space:]]$