I had a similar story just come to closure not too long ago:
Back in April, I left my work phone on a flight from PIT-EWR. I realized I had left it on the flight after moving to the UC, went back to the gate and the plane had already left. No turn ins to lost and found. I wrote the phone off and went on my way to AMS.
FFWD to about a month ago, I got an email from a nice lady at the lost and found depot at IAH saying they had a phone they think belonged to me (not sure how as I never filed a report) and asked me for details. Provided the details, the woman confirmed and overnighted the phone to my house. Received in perfect condition - easily one of my more favorable United CS moments.