Just one command can dramatically improve the safety of your MacBook.
It can help you to find your lost MacBook or other Apple device.
sudo defaults write /Library/Preferences/com.apple.loginwindow \
LoginwindowText \
"If you find my notebook mail me to\
or call me"
Each time when someone will see your login screen, he’ll sees your message:
If you find my notebook mail me to
or call me
So he can to write a message to you, if he found your MacBook and want to return it.