A few years ago, at Glasgow, I checked the suitcase, passed through security and went to the gate.
We didn't get on so, for some reason, had to go back and reclaim suitcase before checking in again.
Second time through security they found the Swiss Army knife which had, inadvertently, been in my handbaggage all the time. Security guy apologised for confiscating it. All over in seconds; no police involvement and off we went.