Men or mice?
Fedex guys often don't know how to knock. They don't care if you get our package or not. They might knock like a mouse, and if you are in the back and don't hear them, you don't get your package. Leave a big sign in the middle of the door with large letters saying KNOCK LOUD. Have your information on their computer at fedex stating that the driver should KNOCK LOUD when they come so you can hear them. Otherwise you have to go and chase the package. I got sick of the drama and got a mailbox at a staffed location. They are always there when the Fedex guy comes, so there was no problem there.