diff --git a/docs/runbooks/althing-deploy.md b/docs/runbooks/althing-deploy.md
index b7946d8..53ca13d 100644
--- a/docs/runbooks/althing-deploy.md
+++ b/docs/runbooks/althing-deploy.md
@@ -157,6 +157,29 @@ The 2026-09-01 lesson was *compare the hook list, not the version string*. This
 is the same lesson one turn deeper: here the hook list was identical too, and
 only the file contents moved.
 
+## A seat already running when the plugin lands never auto-declares — leave it
+
+The SessionStart hook fires at session start and nowhere else, so any session
+that was already running when a plugin deploy landed keeps its old channel
+until it restarts. After the 3.3.1 deploy that was **eight of seventeen live
+seats**, all still on `fifo`.
+
+**Operator ruling 2026-09-02: leave them.** They are reachable now, the post
+office holds mail regardless, and each self-corrects at its next session start.
+The residual exposure is that a fifo waiter is what Claude Code 2.1.257 reaps —
+one seat was reaped three times in a morning — and a reap converts a healthy
+seat into a silent one until the next restart. That costs timeliness, never
+mail.
+
+⚠ **Do not mass-message the affected seats.** Standing operator directive: no
+unsolicited fleet notification, ever, unless asked. Direct correspondence with
+a counterparty about work in hand is fine; sweeping the handle list is not.
+Audit it, report the count, and let him decide — as he did here.
+
+The one-liner, for a seat that asks or an operator who wants one moved:
+
+    althing-route declare --discover-pid
+
 ## ⚠ The `cc` channel is an undocumented interface, taken deliberately
 
 From 3.3.0 a Claude Code seat is poked over its own message socket