On Saturday, a friend came into the house from playing tennis in the garden and said "How's the Boat Race?" "You'll never believe this," I said, "but it's been stopped by a protester." "Bloody hell," said my friend, "did he streak?"

My first impulse was to scoff at his stupidity – yeah right, a naked protester ran across the Thames – until I saw that his puzzlement held an important truth. Which is that we have not the faintest idea how security is likely to be breached in the massive public events that are heading our way this summer.

The Royal flotilla up the Thames in early June, from Chelsea to Tower Bridge, will surely offer an unmissable, slow-moving target to malcontents of every stripe. As Anthony Glees, a university professor of security and intelligence services, puts it, "The security services have to find a way to secure seven miles of river, seven miles of footpaths, seven miles of airspace, seven miles of homes and apartments." So London police are spending half their Jubilee security allocation of £100m on deploying extra coppers in escort boats, patrolling the shoreline and positioning snipers on buildings overlooking the route.

Marvellous. But really, will that stop another resourceful imbecile like Trenton Oldfield from quietly entering the river from a sewage outflow pipe beneath the Tower Hotel, swimming a fast underwater crawl and emerging in front of the royal barge holding up a banner saying "STOP BEING ELITIST, MA'AM"? The Olympics represents another massive rumpus-room of opportunities for the deranged and the meglomaniacal. The Home Office is braced for an attack. In January, Theresa May gave a stirring speech to boast about the 23,700 security personnel at Locog sites, the hundreds of thousands of flatfeet inside and outside 36 competition venues. She mentioned the ironclad security at Olympic Park, the spankingly improved "airwave emergency services radio system", the screening and background-checking of everyone with an accreditation pass, the clampdown on "encampment equipment", the neutralising of "hacktivist" groups and cyber crime, the support of the armed forces in "bomb disposal and enhanced air security over London".

Excellent. But will it prevent another attention-seeking birdbrain from having his moment in front of a global TV audience of four billion, by swimming around with a dorsal fin attached to his back, ruining the sailing races in Dorset or the canoe slalom in Hertfordshire? The point is, we can anticipate what to do about attacks by helicopter gunships, long-range missiles and toxic spam; what we can't budget for are the small-scale disruptions by the muddle-headed and politically confused of whom we saw a prime example on Saturday. The people currently sitting in their mothers' basements plotting their bid for stardom: extinguishing the Olympic flame, as a bearer runs past, with a well-flung face-flannel; ballsing up the women's beach volleyball with an obscene sandcastle; putting a brace of ferrets in a rucksack, heading for the open-to-the-public Cycling Road Track and releasing them in front of the peloton. That, I'm afraid, is what we have to fear – the honourable British traditions of piffling protest and footling defiance.

Which one is the robot?

Weird sight of the week was that of Geminoid F, which is not a brand of skin ointment (you're thinking of Germolene) but "the world's most intelligent robot". Built in Japan two years ago, she was unveiled this week in Hong Kong by her creator, Professor Hiroshi Ishiguro, whose previous 1980s creation, "Kazuo", won the Booker Prize for The Remains of the Day (only kidding). Germi can talk and sing like a human (well – up to a point) and can manage 65 different facial expressions, though her default setting is a passive-aggressive sulk.

The online-hater fraternity went into paroxysms of delight about her resemblance to certain Botoxed singers and dim boy bands, but I was struck by something else. It wasn't the android, with her blinking eyes and shy smile, that I found creepy, but her minder – the anonymous, dark-haired twentysomething Japanese girl from whom she was copied.

As the pair posed for the camera, the minder stroked the robot's cheek, patted her hair and raised her arm, all the time smiling indulgently as if encouraging a young relative to speak up for herself. Any minute now, I thought, she's going to say, "Sorry – she's a bit shy in front of strangers."

The rest of us can usually tell a robot from a human (look at the eyes, duh) but this girl, like a six-year-old playing with her doll, seemed unsure. Perhaps she was manufacturing an emotion for the cameras. But isn't that just what Ms Geminoid F was designed to do?

j.walsh@independent.co.uk