diff --git a/ch09_fees.adoc b/ch09_fees.adoc
index 8f31aace..dffc37bf 100644
--- a/ch09_fees.adoc
+++ b/ch09_fees.adoc
@@ -123,7 +123,7 @@ fee rates.
 
 [WARNING]
 ====
-Be careful accepting input for fee rates.  If a user copies and pastes a
+Be careful ((("absurd fees")))((("excessive fees")))((("transaction fees", "overpaying")))((("overpaying transaction fees")))accepting input for fee rates.  If a user copies and pastes a
 fee rate printed in one denominator into a field using a different
 enumerator, they could overpay fees by 1,000 times.  If they instead
 switch the enumerator, they could theoretically overpay by 100,000,000