I've seen one time where a guy took someone's laptop along with his and didn't realize it. Owner comes up and says her laptop is missing and we're trying to find it. About to start calling the security center to review the tapes when the guy comes back apologizing about taking the laptop.

He had placed his laptop in the wrong pocket of his laptop case and put the other person's laptop in the other pocket. He said he realized his bag was heavier than usual and noticed he had two laptops in his bag and returned back to the checkpoint. There they spent the next minute booting up the laptops to make sure they had the correct ones.

That story thankfully had a happy ending.

One time had this Japanese couple were looking for their shopping bag at the x-ray table. They described it as brightly green colored and two bottles of wine in it (before the liquid ban). We find it all the way at the end and when we go up to the person next to it asking if it's his, he says yes, the bag belonged to him. We the couple and the rest of us go back to the front of the checkpoint trying to see if they left it outside and see no green bag to be found. Go back to the end of the table and find the guy gone, but the green bag still there.

Still a bit confused to this day how that guy was claiming the brightly green shopping bag belonged to him. I guess he realized he did not really have a green shopping bag and just left.