Flash mob storms London

The oddest thing about this BBC NEWS story on the UK's first "flash mob" (at a SofaUK in London, if, like me, you somehow missed it) is the following sentence:
"But some fear [sic] the craze could die out as soon as it started thanks to the over-interested media and over-reaction by the police."
OK, work with me on this: the article has just taken a page to explain very carefully and sensibly that the flash mob's whole point is that it is essentially pointless. So, if a thing's existence is pointless, its ceasing to exist is similarly unprofound. So, what is the "fear" all about?