I've never had any lost items returned on a united flight. 3 different occasions entering SF airport 2 sets of headphones and cushion. Another time entering Lisbon. I had exact seat numbers, 3 biz class, and in 2 cases knew they were left on the seat. Other times were in seat pocket. Twice I phoned from lounge just minutes after arriving.

Obviously pocked by cleaners. United online lost and found is useless, pointless.