diff --git a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
index bdb578de..1ea0d2d1 100644
--- a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
+++ b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
@@ -70,7 +70,7 @@ names the principle that settles it, and is cited as "design 47 G A-n".
   supplies it.
 - **A-18** (§587, §305; principle 7) What G retires leaves no trace: the gate's record type drops the `remove` operation
   and `OpRemove` (§587: a removal is no operation), and its `table`, `recheck` and `close` go with their handlers and
-  tools (§305). `checks`, which no line retires, stays.
+  tools (§305). `checks` goes too, as §431 retires it with the merge states; the check is the runner's now (G-2).
 - **A-19** (§641, §556; principles 1, 7 and 2) `HearSeatEvents` learns that a stream is kept last per subject from the
   stream's own info on the bus, with no new parameter; its ordered read at the start filters on the same subjects as its
   durable; the read's messages go to the same handler as the durable's, so one path handles both; it names the read