This is what I don't get.
That Thursday, two days before one of their most important games in years, you might expet even a few Karenbrough fans to be interested in watching their heroes train. So a young man in casual clothes taking photos on his phone would be nothing unusual.
Remember, at this stage there is no reason to suspect a football spy to be involved. Yet their security staff get all officious, demand that he delete any photos or videos and follow him to the clubhouse toilets. Then go to the trouble of allegedly finding out his name from a credit card transaction and search through SFC website photos for a possible match.
The only photograph that they have published is low definition and partly obscured by his phone. That is not enough on its own to positively identify anyone. Why were they so absolutely convinced that he was a Southampton FC employee? Paranoia is not enough to explain their behaviour.
Unless they had further information.