Move along, nothing to see here.

"Move along, nothing to see here". I've seen this so many times, always posted by conspiracy theorists of one description or another. The idea seems to be that, if something happens that contradicts the brainwashing/ 'official story'/ propaganda etc., the authorities (police, army or whoever) turn up and quickly shoo everyone away so we can't see it.

It's an oft-repeated meme, but I have yet to witness anything remotely like this myself, so I was wondering if anyone else had actually seen this happening? Either physical events or an electronic version will do.