Oren wrote:

In the James Caan movie (1981) "Thief", they sprayed the bell alarms
with expanding foam, let is set and went to work on the bank..

They did the same in the robbery I mentioned, as well as cutting the phone
lines in multiple locations just to make sure they got the right line.

Another cute trick I saw in a commercial burglary involved opening a locked
door by using a chisel to cut out a chunk of door frame so the still-locked
door could swing open with the bolt still sticking out of the lock. Those
aluminum-clad wood door frames common in commercial properties look way
tougher than they are. These days cordless power tools mean they don't have
to use chisels anymore. One place I worked was hit by burglars who pried an
air vent off an outside wall to get into an electrical/phone utility room,
from there they cut through a wall with a cordless saw and got to where they
wanted to be.

The thing about criminals is they don't think like law-abiding people. A
law-abiding person sees a locked door and concludes they can't go through
that door, while a burglar looks at the same door and sees the eleven ways
he knows to go through that door without a key. IMO most of the locks etc.
the average person relies on are junk because they can easily be defeated by
a thief with just a little knowledge and maybe a screwdriver. Years ago I
saw a video called B&E A to Z in which the security consultants in the video
blew through a wide range of common home and business locks etc. just about
as fast as if they had keys, it was amazing to watch. Some of the methods
were ridiculously simple, like knocking out the hinge pins to open a door,
or popping open a popular household lock with just a screwdriver, easy
stuff. So you put in a nice strong door and frame with a good lock, great,
now how about that A/C vent up on the roof, how secure is that? Oops.

Having worked for companies that were burglarized over the years I've
learned all you can do is raise the bar until the value of what you have
inside is insufficient to attract the grade of burglar who can defeat
whatever security measures you have. You can keep out most of the pack
provided you're willing to spend a little money, but if you have a
collection of extremely valuable gold coins or something, probably best to
keep that info to yourself.