diff --git a/.github/workflows/redeploy-tenants-on-main.yml b/.github/workflows/redeploy-tenants-on-main.yml
index efacbe69..46743347 100644
--- a/.github/workflows/redeploy-tenants-on-main.yml
+++ b/.github/workflows/redeploy-tenants-on-main.yml
@@ -306,6 +306,17 @@ jobs:
           if [ $UNREACHABLE_COUNT -gt 0 ]; then
             echo "::warning::$UNREACHABLE_COUNT tenant(s) unreachable post-redeploy. Likely benign teardown race — CP healthz monitor catches real outages."
           fi
+
+          # Belt-and-suspenders sanity floor: same logic as the staging
+          # variant — see that file's comment for the full rationale.
+          # Floor only applies when fleet >= 4; below that, canary-verify
+          # is the actual gate.
+          TOTAL_VERIFIED=${#SLUGS[@]}
+          if [ $TOTAL_VERIFIED -ge 4 ] && [ $UNREACHABLE_COUNT -gt $((TOTAL_VERIFIED / 2)) ]; then
+            echo "::error::$UNREACHABLE_COUNT of $TOTAL_VERIFIED tenant(s) unreachable — exceeds 50% threshold on a fleet large enough that this signals a real outage, not teardown race."
+            exit 1
+          fi
+
           if [ $STALE_COUNT -gt 0 ]; then
             echo "::error::$STALE_COUNT tenant(s) returned a stale SHA. ssm_status=Success was misleading — see job summary."
             exit 1
diff --git a/.github/workflows/redeploy-tenants-on-staging.yml b/.github/workflows/redeploy-tenants-on-staging.yml
index 125f25c1..7f191e8d 100644
--- a/.github/workflows/redeploy-tenants-on-staging.yml
+++ b/.github/workflows/redeploy-tenants-on-staging.yml
@@ -283,6 +283,25 @@ jobs:
           if [ $UNREACHABLE_COUNT -gt 0 ]; then
             echo "::warning::$UNREACHABLE_COUNT staging tenant(s) unreachable post-redeploy. Likely benign teardown race — CP healthz monitor catches real outages."
           fi
+
+          # Belt-and-suspenders sanity floor: if MORE than half the fleet is
+          # unreachable AND the fleet is large enough that "half down" is
+          # statistically meaningful, this is a real outage (e.g. new image
+          # crashes on startup), not a teardown race. Hard-fail.
+          #
+          # Floor only applies when TOTAL_VERIFIED >= 4 — below that, the
+          # canary-verify step is the actual gate for "all tenants down"
+          # detection (it runs against the canary first and aborts the
+          # rollout if the canary fails to come up). Without the >=4 gate,
+          # a 1-tenant fleet (e.g. a single ephemeral e2e-* tenant on a
+          # quiet staging push) would re-flake on the exact teardown-race
+          # condition #2402 fixed: 1 of 1 unreachable = 100% > 50% → fail.
+          TOTAL_VERIFIED=${#SLUGS[@]}
+          if [ $TOTAL_VERIFIED -ge 4 ] && [ $UNREACHABLE_COUNT -gt $((TOTAL_VERIFIED / 2)) ]; then
+            echo "::error::$UNREACHABLE_COUNT of $TOTAL_VERIFIED staging tenant(s) unreachable — exceeds 50% threshold on a fleet large enough that this signals a real outage, not teardown race."
+            exit 1
+          fi
+
           if [ $STALE_COUNT -gt 0 ]; then
             echo "::error::$STALE_COUNT staging tenant(s) returned a stale SHA. ssm_status=Success was misleading — see job summary."
             exit 1