The owner is given the option to either go put it back in their car, ship it to themselves for a small fee, or let the TSA take it. It's not like "hey, you screwed up and now you lose this item for good!"
“small” fee my ass. When the TSA confiscated a camping knife I kept in my backpack and forgot about, the agent said it’s about $20. Also, for someone who boards in 30 minutes with a TSA line just as long, they don’t really have a choice: it’s lose the item, or miss your flight. So I had to let them take it.
