Leaving it out "in the wild" was a mistake (IMHO). You would have been better off stashing it in your closet until UPS finally gets someone over at your convenience or gives you the go-ahead to drop it off at one of their stores. If anyone from the gardener to the mailman to a random stranger picks it up, you're the last person to have signed for it. Guess who they could chose to come after?
Hopefully it works out all right, but if they didn't pick it up and it's still there, I'd just tell them that you'll drop it off at one of their locations. If they don't like that, they can pick it up between 5pm and 8 pm Monday to Friday, or whatever works for you. Anything else is their problem.
Do NOT give it to the person who's name is on it. His/her phone is likely on it's way, as you've already mentioned. And again, with you being the last person who signed for the phone in your sweaty hand, all they have to do is say they never got the phone from you. Any compensation between Apple and that customer are just that... Between Apple and that customer. Not your problem.
As far as that goes... Repeat after me... "Not my problem". Use that when you talk to UPS, and you tell them that you can't take time off from work to sit there waiting for them to pick up a phone that they delivered incorrectly.
I had Dell ship me an extra laptop a couple of years ago. They wanted to send someone to my place to pick it up, but as a contract employee, I wasn't giving up an afternoon's wages to sit there waiting for UPS to drop by. I eventually got the go-ahead to drop it off at a UPS office. It was a pain in the butt for someone else's mistake.
C