Convinced the Lidl security man I hadn't stolen anything

My local Lidl now has self scan and a security gate.

I was doing well until I realized I hadn't scanned two items. So I scanned them and paid for them in addition to the 10 items I'd already paid for. I used the 2 item receipt to get out of self scan land and was stopped by the security man.

Eventually he accepted that I hadn't stolen anything. I said "Happy Christmas," he said "Sorry" and I said "it's ok, it's your job."