When I was growing up, the dog we had, a lovely Lab/Chow mix called Sadie, would bark at the mail carrier every day. This clearly was very effective: every day, she scared the mail carrier away. We referred to this as the Sadie Method of Homeland Security.
There are two possible catastrophes she was preventing:
- The mail carrier could break into our house and steal our things and possibly murder all of us.
- The mail carrier would just stay on the porch, and the next day another one would come by, and soon there would be so many postal workers on the porch that we would be unable to access the house.