I wonder if hearing/language an issue here, all staff seem to think all people can hear or speak english, my partner is deaf and they often ask her a question and assume because she does not answer its an affirmative, I then step in. Maybe he was asked "malta Sir", no answer so not stopped, either because he did not hear or did not understand.
I did think all boarding cards scanned so has this gone wrong after the boarding gate.
This is not an isolated gate issue, recently at leeds we were talking to a young lady in the queue in front of us, when she got to show her boarding card/passport to Jet2 staff, staff member found she was not holding her passport, but that of her sister. It turned out that her sister had already boarded using an incorrect passport.
The sisters were both married and their surnames different, so shows gate staff asleep on the job..