There are media reports of bombs on the London Underground, and you’re outside Kings Cross station, which is closed. An angry mob is building up. There’s a guy shouting into his mobile phone. Is he trying to call loved ones and becoming frustrated because he keeps getting the answer machine? Or is he a first responder who needs to make himself heard above the crowd as he checks back into his command post? During the 7/7 London bomb attacks, some people thought the bombs had been remotely triggered by mobile phone. Indeed, when the mobile phone networks collapsed under the weight of calls, the BBC figured that the security services had shut them down. So is that guy on his phone actually a terrorist? Maybe you should take his picture with your own phone and log it on Twitter. Or maybe you shouldn’t. See http://www.bbc.co.uk/news/technology-22214511