[mothered]

I'm sure PP will check the tracking, and I don't think UPS will deliver without a signature.

Tracking cannot be used to confirm deliveries. It only concludes that It's been successfully delivered to "an address", and cannot mark a package delivered to "a person". There's a huge difference between the two, with the latter rendering It Inconclusive.

As for a signature, that's also useless- a passerby or the driver himself, could've signed for It.