They were definitely manually controlled by the stewards just beyond the turnstile. The steward standing in front of me told me so when I asked him what the hold-up was, as there'd been a red cross on the scanner for a couple of minutes and we'd not moved anywhere. I then saw the steward beyond...
The ticket scanners were manually controlled by the stewards standing just beyond them doing one of the searches. They were turned off constantly to stop anyone managing to evade being searched.