There should be the option to leave minus stars.
We have experienced several episodes of expensive parcels thrown over the back fence. We asked one driver about why he did this and he said that "....the Sat Nav took me round the back and you can't expect me to walk round the front!". We have also had expensive electrical goods left out in the open without a note being put through the door. One parcel was in a neighbours front garden for several days before it was found.