FedEx drivers get paid by the package, not by the hour (independant contractors). The more they deliver, the more they get paid. They couldnt give a crap about who signs for it, just as long as it was delivered. Also, if it was delivered within 100ft of your residence, FedEx considers it an 'On Target' delivery (Ive been down this road with them on this very issue).
Also, I only use USPS for 90% of my shipping (brother is a letter carrier) and UPS for the rest and expidited shipping. Only one issue in the last 12 years with either service.
Fordman