A hands-on workaround to avoid your laptop getting stolen in a security scanning. See http://www.echeng.com/journal/2016/5/23/tsa-gave-my-macbook-pro-to-another-passenger-at-lax-and-now-its-gone

gistfile1.txt

#!/bin/bash
# Run this script just before you put the laptop in the bin for security scanning.
# You can add the seconds the laptop will be waiting before speaking. The default
# is waiting for 180 seconds (3 minutes).

# Switch to the login screen, effectively locking the screen.
function lockscreen() {
  /System/Library/CoreServices/"Menu Extras"/User.menu/Contents/Resources/CGSession -suspend
}

function voice() {
  echo "Locking screen now..."
  sleep 1;  lockscreen
  sleep $1; echo "Hit Ctrl-C to interrupt the voices."
  osascript -e "set Volume 10"
  while :; do
    # You could be creative here!
    sleep 5; say -v Bell -r 50 dong dong
    sleep 1; say -v Victoria -r 100 "I don't belong to you"
  done
}

function volume_off() {
  osascript -e "set Volume 0"
  echo; echo "Turned volume off."
  exit
}

trap volume_off INT
wait=$1
if [[ $# -lt 1 ]]; then wait=180; fi
echo "Caffeinated. Waiting $wait seconds then starting voice..."
caffeinate -i & voice $wait

# caffeinate doesn't always work. InsomniaX seems to interfere.
# In such a case you have to disable sleep manually.