Usually they arrive in an unmarked car not a well-marked locksmith truck or van. 

You are wonder why did they drill out your locks and they never once even tried to pick the lock open or find any other method of gaining entry into the location without having to destroy the locks.  Any professional locksmith will tell you the absolute last choice is to drill out the locks.  A professional locksmith has several method of gaining entry into a location that will not damage any of your property.

The same is true with your vehicle.  If you leave your keys inside your vehicle the professional locksmith can gain entry into your vehicle without causing your vehicle any damage.  The scammer will play games with your and charge you hundreds of dollars to open your vehicle.  In the event you actually lose your key to your vehicle they will destroy your vehicle cost you hundreds of dollars to repair.

Now I will teach you How to protect yourself from ever being ripped off by the locksmith scammers.

The first thing you need to do is make sure you have a few spare house keys and a few spare keys for your vehicle.  Hide a spare key outside your house.  In the event you are locked out you can always get your spare key and gain entry into your home and it will not cost you a penny.