diff --git a/README.md b/README.md
index 8f97b05..31f3b89 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,7 @@ user_details
 - [] exactly same time -> deny registration
 - [] automatically add regular planned trip
 - [] same day+time: aggregate stats (x people, of which y cox and z rower)
+- [] Lock trip; noone can register anymore