Call me naive, but I was actually quite shocked to see this amateur footage of Nick Robinson grabbing and then stamping repeatedly on an anti-war placard that had been held up behind him as he was speaking to camera. Now, if the protester had invaded a news studio, it would have been reasonable enough to confiscate his placard (although even then I'm not sure what the law would say about gratuitous attempts to vandalise or destroy it), but the incident happened on College Green, which to the best of my knowledge is a public space. Just what extra-judicial powers do the media really imagine they have to act against someone who is doing something perfectly legal that they happen to find a bit irritating?
What made Robinson's actions even more unwise, of course, is that by stamping on the placard, he gave the impression to some of expressing a view about the anti-war message itself. That almost certainly wasn't his intention, but as Sunny Hundal points out, would he have dared to risk even the perception of bias had the protest been about a subject that newspapers really care about, like immigration? A bit like the Frankie Boyle incident earlier in the year, the heartening thing here is that the internet now empowers the person who feels they have been wronged by a public figure to bypass the mainstream media, get their side of the story out unmediated, and then allow the public to make up their own minds. I think the protester's mistake in the video, though, was to confront Robinson about expressing pro-war views, which let him off the hook as it hadn't been established that this is what he'd been doing. A charge of 'stamping on the public's right to free expression' would have been a lot trickier to answer.