She's just too lazy to get out of the car and walk the few steps to your door to leave it. File a complaint with your postmaster. I had an issue a couple years ago where if I received a parcel that was registered or needed a signature the guy would just leave a notice to come to the Post office to pick it up because I was not home when he came. After I saw him drive past my house one time and never even tried to deliver it I realized what he was doing. I filed a complaint with the postmaster. He said the guy told him he didn't know he was supposed to attempt delivery.