Yeah, in my experience FedEx drivers absolutely LOVE saying they “attempted delivery of my package, but nobody was home,” so I have to go get it from the depot. But I 100% was home, working from home all day, and they 100% never came.
That sounds like internal verification uses GPS. So in most cases it's going to be the customer's word against the astonishingly lazy driver's evidence.
I called them and questioned them about this - they didn't even come down my street, and yet claimed that they "attempted delivery". The customer service person was honest enough to say there was no code for the driver to say "too busy, can't meet my unrealistic targets".