The harder you make it to break in... The more damage they do breaking in.
However there is such a thing as a burglar alarm.. Here are two of my favorites.
One. the P-K9 System
Burglar breaks in and is loading the family silver in his pillow case, hears a voice "Jesus is watching you".. Freezes, then slowly looks about and seeing nothing gets back to work, again he hears "Jesus is watching you",, on the 3rd time he determines it is the family parrot who is talking.
So what, you are just a parrot what can you do?
"Oh I'm not Jesus, I'm Moses and Jesus is watching you"
Moses, what kind of idiot names his parrot Moses?
"The same kind that names his Rototiller Jesus, and Jesus is watching you".
(Now that is one ALARMED burgler)
The next one is easier, requires less clean up, and no large bags of dog food.
The Remington CD system
Sensors are tripped by the break in start a high quality sound system up and also start a CD playing, about 30-60 seconds of digital silence followed by the sound of a Remington Pump Action Shotgun being racked. That's all, no gun, just the sound effect.