I work in a pretty bad area. I've had numerous "denial of signatures", and I've had to be a little crafty to get the DFU's signed off on. One lady I delivered to was getting a box from Movado. I saw this, and commented on it when she answered the door. I said "Movado? They make nice watches" She said "I got my husband a 1200 watch for his birthday! He'll be so happy!" I guess he wasn't happy with the credit card bill later, so a few weeks go by and I get a denial of signature. I knock, and the same lady answers the door. I say "Hi ma'am, I'm just doing a follow-up on the Movado watch I delivered here back on so-and-so date" She says right to my face "I never go it. That's not my signature". I then tell her "I had a conversation with you about how much the watch cost, and you told me $1200. Oh, look here, what a coincidence. That's exactly how much this tracer is for, and you did sign for this. You can sign off that you got the watch, or never get another package from UPS. Your choice" She was madder than Hell, but there was NO way I was letting her get a $1200 refund from UPS when I know she got it. She refused to sign, so I went to LP and told them exactly what happened. She never got the money, and coincidentally every package she ordered always got refused. Must've been that "other" lady refusing all of her stuff. Oh well.
When people try to say they didn't get their new phone that I DR'd, I'll call the number on the tracer and see if they answer. Soon as they do I'll tell them who I am and that I need them to sign-off on the tracer. Soon as they answer the door I'll call the same phone. Many times it's on them. I'll say "In order for me to verify you didn't get your new phone, I need to check the one you're using to see if the serial numbers don't match" So far I have 100% success rate in the hood for positive DFU's concerning cell phones. Scammers aren't very smart.