diff --git a/hack/install-ate.sh b/hack/install-ate.sh
index 5ace949c2b..14b7f2c849 100755
--- a/hack/install-ate.sh
+++ b/hack/install-ate.sh
@@ -38,6 +38,11 @@ fi
 # ATE_DEMOS is an array that registers the prefix name of the demo functions.
 ATE_DEMOS=()
 
+# Called by a ${demo}_cmdline handler for an argument it does not own.
+ate_demo_flag_unhandled() {
+  ATE_DEMO_FLAG_HANDLED=false
+}
+
 # Include demos.
 source "${ROOT}"/hack/install-demo-counter.sh
 source "${ROOT}"/hack/install-demo-egress.sh
@@ -627,7 +632,7 @@ get_actor_status() {
 }
 
 # prepare_actor_for_delete suspends (or resumes then suspends) until DeleteActor
-# is allowed. Actors must be STATUS_SUSPENDED before deletion.
+# accepts the actor: STATUS_SUSPENDED, STATUS_CRASHED, or STATUS_DELETING.
 prepare_actor_for_delete() {
   local actor_name="$1"
   local atespace="$2"
@@ -641,7 +646,7 @@ prepare_actor_for_delete() {
     fi
 
     case "${status}" in
-      STATUS_SUSPENDED)
+      STATUS_SUSPENDED | STATUS_CRASHED | STATUS_DELETING)
         return 0
         ;;
       STATUS_PAUSED)
@@ -660,7 +665,7 @@ prepare_actor_for_delete() {
     sleep 2
   done
 
-  echo "timed out waiting for actor ${actor_name} to reach STATUS_SUSPENDED" >&2
+  echo "timed out waiting for actor ${actor_name} to become deletable" >&2
   return 1
 }
 
@@ -849,17 +854,21 @@ esac
 store_backend >/dev/null
 
 while [[ "$#" -gt 0 ]]; do
-  # Run ${demo}_cmdline if it exists. If it returns 0, then we successfully
-  # handled this argument and can continue. Otherwise, fallthrough to check
-  # the other arguments.
+  # Handlers signal an unclaimed argument via ate_demo_flag_unhandled, not exit
+  # status: an `if`-condition call would suppress errexit in the whole call tree.
+  ATE_DEMO_FLAG_HANDLED=false
   for demo_name in "${ATE_DEMOS[@]}"; do
-    if declare -F "${demo_name}_cmdline" >/dev/null 2>&1; then
-      if "${demo_name}_cmdline" "$1"; then
-        shift
-        continue 2
-      fi
+    declare -F "${demo_name}_cmdline" >/dev/null 2>&1 || continue
+    ATE_DEMO_FLAG_HANDLED=true
+    "${demo_name}_cmdline" "$1"
+    if [[ "${ATE_DEMO_FLAG_HANDLED}" == "true" ]]; then
+      break
     fi
   done
+  if [[ "${ATE_DEMO_FLAG_HANDLED}" == "true" ]]; then
+    shift
+    continue
+  fi
 
   case $1 in
     --ateapi-client-auth=*) ATE_ATEAPI_CLIENT_AUTH="${1#*=}" ;;
diff --git a/hack/install-demo-autoscaled-workerpool.sh b/hack/install-demo-autoscaled-workerpool.sh
index adb2abf67a..26b16e6f0b 100644
--- a/hack/install-demo-autoscaled-workerpool.sh
+++ b/hack/install-demo-autoscaled-workerpool.sh
@@ -27,10 +27,9 @@ demo-autoscaled-workerpool_cmdline() {
     --deploy-demo-autoscaled-workerpool) demo-autoscaled-workerpool_deploy ;;
     --delete-demo-autoscaled-workerpool) demo-autoscaled-workerpool_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-autoscaled-workerpool_deploy() {
diff --git a/hack/install-demo-claude-code-multiplex.sh b/hack/install-demo-claude-code-multiplex.sh
index 5a5e3b9778..1e1d2d07b1 100644
--- a/hack/install-demo-claude-code-multiplex.sh
+++ b/hack/install-demo-claude-code-multiplex.sh
@@ -23,10 +23,9 @@ demo-claude-code-multiplex_cmdline() {
     --deploy-demo-claude-code-multiplex) demo-claude-code-multiplex_deploy ;;
     --delete-demo-claude-code-multiplex) demo-claude-code-multiplex_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 # Build the workload image, push to ${KO_DOCKER_REPO}, and echo the resolved
diff --git a/hack/install-demo-counter.sh b/hack/install-demo-counter.sh
index c2248271e3..7a25bdb668 100644
--- a/hack/install-demo-counter.sh
+++ b/hack/install-demo-counter.sh
@@ -28,10 +28,9 @@ demo-counter_cmdline() {
     --deploy-demo-counter-with-external-volume) demo-counter_deploy "true" ;;
     --delete-demo-counter) demo-counter_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-counter_deploy() {
diff --git a/hack/install-demo-egress.sh b/hack/install-demo-egress.sh
index e4e0074a9d..3140430510 100644
--- a/hack/install-demo-egress.sh
+++ b/hack/install-demo-egress.sh
@@ -23,10 +23,9 @@ demo-egress_cmdline() {
     --deploy-demo-egress) demo-egress_deploy ;;
     --delete-demo-egress) demo-egress_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-egress_deploy() {
diff --git a/hack/install-demo-multi-template.sh b/hack/install-demo-multi-template.sh
index 0d05582846..2b123170af 100644
--- a/hack/install-demo-multi-template.sh
+++ b/hack/install-demo-multi-template.sh
@@ -23,10 +23,9 @@ demo-multi-template_cmdline() {
     --deploy-demo-multi-template) demo-multi-template_deploy ;;
     --delete-demo-multi-template) demo-multi-template_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-multi-template_deploy() {
diff --git a/hack/install-demo-parking.sh b/hack/install-demo-parking.sh
index 72d72e826c..1af3751408 100644
--- a/hack/install-demo-parking.sh
+++ b/hack/install-demo-parking.sh
@@ -23,10 +23,9 @@ demo-parking_cmdline() {
     --deploy-demo-parking) demo-parking_deploy ;;
     --delete-demo-parking) demo-parking_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-parking_deploy() {
diff --git a/hack/install-demo-sandbox.sh b/hack/install-demo-sandbox.sh
index fb32097498..589a9f339b 100644
--- a/hack/install-demo-sandbox.sh
+++ b/hack/install-demo-sandbox.sh
@@ -23,10 +23,9 @@ demo-sandbox_cmdline() {
     --deploy-demo-sandbox) demo-sandbox_deploy ;;
     --delete-demo-sandbox) demo-sandbox_delete ;;
     *)
-      return 1
+      ate_demo_flag_unhandled
       ;;
   esac
-  return 0
 }
 
 demo-sandbox_deploy() {