diff --git a/dom.bs b/dom.bs
index 71ee81ab..7d92d437 100644
--- a/dom.bs
+++ b/dom.bs
@@ -1121,8 +1121,7 @@ participate in a tree structure.</p>
  <a for="service worker">script resource</a>'s
  <a for="script resource">has ever been evaluated flag</a> is set, and <var>listener</var>'s
  <a for="event listener">type</a> matches the {{Event/type}} attribute value of any of the
- <a>service worker events</a>, then <a>report a warning to the console</a> that this might not give
- the expected results. [[!SERVICE-WORKERS]]
+ <a>service worker events</a>, then throws INVALID_MODIFICATION_ERROR exception. [[!SERVICE-WORKERS]]
 
  <li><p>If <var>listener</var>'s <a for="event listener">signal</a> is not null and is
  [=AbortSignal/aborted=], then return.