diff --git a/bin/adb b/bin/adb
index 87ea217..fa8dbdc 100755
--- a/bin/adb
+++ b/bin/adb
@@ -69,8 +69,33 @@ if [ -z "${ANDROID_SERIAL:-}" ]; then
         devices | start-server | kill-server | version | help | connect | disconnect) ;;
         *)
             if [ "$named" = false ]; then
-                serial=$(avd_serial "$real" "$(project_avd)" || true)
-                [ -n "$serial" ] && target=(-s "$serial")
+                avd=$(project_avd)
+                serial=$(avd_serial "$real" "$avd" || true)
+                if [ -n "$serial" ]; then
+                    target=(-s "$serial")
+                else
+                    # This checkout's emulator is not running, and something
+                    # else's is. Handing the call through would drive their
+                    # device -- installing over the app they are looking at,
+                    # or taking their foreground -- and it would look like it
+                    # worked. A physical phone is not somebody's checkout and
+                    # is left alone, which is why this asks for the AVD name
+                    # rather than counting devices.
+                    others=$(running_avds "$real" | awk -F'\t' -v mine="$avd" '$2 != mine')
+                    if [ -n "$others" ]; then
+                        {
+                            echo "adb: '$avd' is not running, and these emulators belong to other checkouts:"
+                            echo "$others" | while IFS=$'\t' read -r s n; do
+                                printf '  %-16s %s\n' "$s" "$n"
+                            done
+                            echo
+                            echo "  emu up                    start this checkout's own"
+                            echo "  adb -s SERIAL ...         or say which you meant"
+                            echo "  ANDROID_SERIAL=SERIAL     for a run of them"
+                        } >&2
+                        exit 1
+                    fi
+                fi
             fi
             ;;
     esac
diff --git a/bin/emu b/bin/emu
index 3449aa9..52630f4 100755
--- a/bin/emu
+++ b/bin/emu
@@ -59,8 +59,15 @@ cmd_list() {
     found=false
     while IFS=$'\t' read -r serial name; do
         found=true
-        port=${serial#emulator-}
-        rss=$(ps -eo rss,args | awk -v p="-port $port" '$0 ~ p && $0 ~ /qemu-system/ {print int($1/1024); exit}')
+        # Matched on the AVD name the emulator was started with, which is
+        # what its process actually carries -- there is no -port in that
+        # command line, and the console port in the serial does not appear
+        # in it. Filtered on the process *name* rather than on the whole
+        # line, so this cannot match the shell running it: that shell's
+        # command line contains this pattern, and a `ps | awk` that matches
+        # itself reports the size of the shell.
+        rss=$(ps -eo rss=,comm=,args= |
+            awk -v want="-avd $name" '$2 ~ /^qemu-system/ && index($0, want) {print int($1/1024); exit}')
         printf '  %-16s %-24s %s\n' "$serial" "$name" "${rss:+$rss MB}"
     done < <(running_avds "$adb")
     [ "$found" = true ] || echo "  (none attached)"